Both these characters are protagonists from series focusing on VRMMORPGs, so there's a good deal of similarities to work with for this debate. Now, to get down to some information about both their respective "games" (for Kirito, we're restricting him to SAO exclusively, none of the subsequent games):

Sword Art Online
SAO is a VRMMORPG centered in the flying castle "Aincrad," which consists of 100 floors. The game consists of a variety of monsters, including a main "Boss" monster which controls each floor and restricts access to the next. Each floor contains cities, towns, and different landscapes and areas.

Players in SAO are unable to magic, but make up for this with a wide and varied amount of melee weapon "skills," the primary of which focuses on swords of different varieties. There are also skills outside of this, such as Cooking, Forging, First-Aid, etc. SAO features a variety of items both similar to those found in real life and unique to Aincrad, such as teleportation crystals.

The World R:2
The World R:2 is a VRMMORPG based off the original The World VRMMORPG, which was brought down due to a fire at the main headquarters servers. When the game came back, it was revamped, with new classes, new character customizations, and several new systems. Similar to the previous game, The World R:2 has massive lore which can be learned through reading through its history. The World R:2, the spiritual successor to the original game, is set 100 years in the future and now utilizes a good deal of steam power, giving it a Steampunk feel, and of the two races (Human and Beast), there are a total of 6 factions.

Players in The World R:2 are able to pick one of 11 classes (after designing their character), each of which has its own strengths and weaknesses, as well as weapons tailored to each class. Each class has its own types of skills, and there are a variety of magic skills that all players are able to utilize (but are specialized in by the magic classes).



Now that we've established a firm base, lets get the characters in question. To note, in the case of Kirito, I will list all his skills as specified on his wiki page. In the case of Haseo, which is a bit more complicated, I'll last all his weapon skills and epitaph skills (no magic, though he can use them) that have been shown in the games, and will limit him to his 3rd form, rather than Xth.

Kirito:
-Horizontal
-Horizontal Square
-Rage Spike
-Slant
-Spinning Shield
-Sonic Leap
-Vertical Square
-Vertical
-Vertical Arc
-Vorpal Strike
-Flash Hit
-Embracer
-Meteor Break
-Double Circular
-Starburst Stream
-The Eclipse
-Arms Blast
-Hypersense
-Mislead
(On this list, the following have been retconned from the wiki for contest purposes: Skill Slots Skills (unless directly sword related) and Escape)

Haseo:
-Gale Blade (Twin Blade)
-Sparrow Counter (Twin Blade)
-Sword Dance (Twin Blade)
-Tri-Strike (Twin Blade)
-Whirlwind (Twin Blade)
-Chaotic Strike (Twin Blade)
-Ghost Falcon (Twin Blade)
-Tiger Blitz (Edge Punisher)
-Twin Moons (Edge Punisher)
-Armor Pierce (Edge Punisher)
-Bone Crusher (Edge Punisher)
-Tiger Strike (Edge Punisher)
-Shell Breaker (Edge Punisher)
-Armor Break (Edge Punisher)
-Wicked Strike (Flick Reaper)
-Lotus Flower (Flick Reaper)
-Reaper's Touch (Flick Reaper)
-Heavenly Wheel (Flick Reaper)
-Reaper's Dance (Flick Reaper)
-Summon Avatar (Skeith)
(On this list, the following have been retconned for contest purposes: all magic skills, Avatar Awakening, Group Skills.)
[Explanation of words beside skills: Beside the skills is the Class Branch it originates from. Twin Blade is a dual-dagger wielding class; Edge Punisher is a broadsword wielding class; and Flick Reaper is a scythe-wielding class. Skeith is the name of Haseo's avatar, which he has as an Epitaph User.]

Finally, I'll list some exploits of each character, to provide a better idea of their skills.

Kirito:
-Beat SAO, which killed players IRL who died in the game.
-Only Dual-Wielder in the game (due to having fastest reaction time)
-Solo'd a majority of SAO, which had the previously mentioned habit of killing people.
-Obtained System Admin abilities.
-Totally had sex with Asuna.

Haseo:
-Despite using the unpopular Adept Rogue class (a Jack-of-Trades class), he became the strongest PKK (Player Killer Killer), earning himself the title "Terror of Death."
-Originally was a high level player in the first game who went by Sora, before being attacked by Skeith. Though he lost his memory, he retained a good deal of his experiences from the time (likely the reason for his advanced skills with said class).
-Despite having his max level character reset to Level 1, he managed to regain a majority of his previous power, alongside a major boost that came in the form of Skeith, who surpasses system boundaries and is able to rewrite and absorb coding from different sources.
-Completely rewrote the internet.


A few more things to note, and then we can all get discussing:
-Kirito's skills require a short charge period, where when the blade glows, the skill will activate.
-Landing enough damage on an opponent allows Haseo to use "RENGEKI," which doubles the damage dealt by a skill.
-Both Kirito and Haseo have access to their System-Breaking skills, meaning Kirito has Admin Access and Haseo can summon the System Breaking Skeith.
-They're both maxed out in levels with their best equipment; however, Kirito is exclusively in SAO gear, and Haseo is in his 3rd form (Flick Reaper access), but not his Xth form.
-There are no healing items or skills, no escape items or skills, and no status effect items or skills.
-This is a battle to the death, or to a yield. Kirito has canonically killed other players before, and as a PKK, Haseo kills players who have killed other players.
-The field of battle is an open plain outside of both players' respective games. There are no obstacles, no abnormalities, simply grass and dirt in a plains fashion.





THIS IS A DEBATE ON CHARACTERS. ANYONE WHO DOES NOT ATTEMPT TO PROPERLY ARGUE, OR POSTS IRRELEVANT STUPIDITY WILL BE INFRACTED AND HAVE THEIR POSTS DELETED. THIS IS ENTIRELY SERIOUS. DO NOT BRING UP OTHER CHARACTERS UNLESS NECESSARY, DO NOT CREATE NEW CONDITIONS, DO NOT FANBOY. DISCUSS, RESEARCH, ARGUE, REBUKE. JUST MAKE SURE YOU AREN'T BULLSHITTING, AND WE'LL ALL BE FINE AND DANDY.

Wow this debate is serious O_O
I'll do my sucky debate after reading all that, okey ;)

Where are they gonna fight?
Kirito plays in SAO while Haseo plays in The World R:2.

Wouldn't Kirito only be able to use his Admin Access in SAO and Haseo can only use System Breaking Skeith in The World R:2?

If so, one will have advantage over the other when the other fight in one's arena.

Kirito steps in The World R:2 -> Haseo wins
Haseo steps in SAO -> Kirito wins

?

Quote from Azure Kite

-The field of battle is an open plain outside of both players' respective games. There are no obstacles, no abnormalities, simply grass and dirt in a plains fashion.

I think this answers your question.

Anyways, time for some of the research I did on Skeith and .hack universe for DTG to come to use again.

Just by checking Flick Reaper class' description, it says it can keep melee attackers away. In this light, he has a slight advantage already. As read in it as well, its an AoE Class built to keep masses of monsters at bay whilst keeping them damaged.

Kirito is mainly a melee type character with a small amount of ranged capability [see episode where he killed a rabbit(?) with a needle] but can do so with accuracy but even then, I'd say the ranged attack such as that would still be in range for a Flick Reaper to push away. However, Kirito is agile, blessed with a reaction time that gave him access to dual-blades he may be able to dodge a few of Haseo's hits and close the distance enough to begin tearing through defenses.

Once the two are in CQC, things begin to side on who is faster. Skills in .hack [correct me if I'm wrong] do have a bit of charge time as well so I'd say they are slightly on par with Haseo a bit faster.

Open for rebuttal.

Is Kirito serious, assuming his life (or someone elses life) depends on this fight?

I don't think so. I'd say his own life is on the line considering he has killed players and Haseo is a PKK.

Quote from Matthew Murphy

Where are they gonna fight?
Kirito plays in SAO while Haseo plays in The World R:2.

Wouldn't Kirito only be able to use his Admin Access in SAO and Haseo can only use System Breaking Skeith in The World R:2?

If so, one will have advantage over the other when the other fight in one's arena.

Kirito steps in The World R:2 -> Haseo wins
Haseo steps in SAO -> Kirito wins

?

As Error said, I gave a location for battle.

Quote from ErrorBlender

Debate (Click to Show)

I think this answers your question.

Anyways, time for some of the research I did on Skeith and .hack universe for DTG to come to use again.

Just by checking Flick Reaper class' description, it says it can keep melee attackers away. In this light, he has a slight advantage already. As read in it as well, its an AoE Class built to keep masses of monsters at bay whilst keeping them damaged.

Kirito is mainly a melee type character with a small amount of ranged capability [see episode where he killed a rabbit(?) with a needle] but can do so with accuracy but even then, I'd say the ranged attack such as that would still be in range for a Flick Reaper to push away. However, Kirito is agile, blessed with a reaction time that gave him access to dual-blades he may be able to dodge a few of Haseo's hits and close the distance enough to begin tearing through defenses.

Once the two are in CQC, things begin to side on who is faster. Skills in .hack [correct me if I'm wrong] do have a bit of charge time as well so I'd say they are slightly on par with Haseo a bit faster.

Open for rebuttal.q

To note, Haseo's class is Adept Rogue, meaning he's able to use the abilities of several classes, to lower efficiency than any of the pure classes. With this, he has access to Dual Daggers, a Broadsword, and a Scythe. He is even able to freely switch between these weapons, meaning that it's possible for him to use his Flick Reaper abilities to keep Kirito at a distance, then match or even surpass his speed by switching to his Dual Daggers (Twin Blade is the fastest class in the game, though it has the lowest damage output). His Broadsword also has sweeping attacks and AOE attacks, making it a strong powerhouse for mid-range.

As for skills, they're considerably quicker for R:2 players, considering it's simply input the command/call the name. Realistically, it would simply take them thinking "this is the skill I'd like to do" and they'd move to perform it. So there is the skill speed advantage on Haseo's side, though as noted, Adept Rogues are Jack-of-Trades. SAO is pretty much specialization, so it's likely that if Kirito can get a strong enough foothold at close range, he'd be using his Dual Blades against Haseo's Dual Daggers, and have a strength and range advantage... though not necessarily an experience advantage. Up for debate.

Quote from Unbounded

Is Kirito serious, assuming his life (or someone elses life) depends on this fight?

Work under the assumption that yes, he is serious.

I checked the timeline of .hack, [correct me again if anything is amiss since you're the expert here Azure, xD] that Haseo started playing R2 on 2016 and service ended on 2018 which gives him a two year experience playing. I am aware that he was once Sora but his memory was erased. Also am aware that being one with Skeith returned Sora to Haseo but I'm unsure if the memory also returned.

SAO ended after two years as well which gives Kirito [though loosely] the same amount of experience in his world.

Ryou Misaki has little combat skills which unlike Kirigaya Kazuto, who has trained in kendo. Though normally this isn't really much but training does carry over in the slightest. VR means that some of the IRL instincts and possibly muscle memory, carries over. Even without skills Kirito is a good fighter. Not to say Haseo isn't but I'm saying is that a small difference is present.

Twin Blades and Dual Wielding seem to be the same; since in SAO only gives it to the player with the fastest reaction time. This gives Kirito some credit on processing things faster on instinct [thanks to training and SAO experience] and be able to block or dodge.

Faster reaction time or faster cast time.
--Kirito------------------Haseo---------

In regards to Haseo's experience, his ganing experience as Sora disappeared from his memory, but he still retained the actual skill level he had, hence why he was able to kill 100 PKs in the Forest of Death event and becomes he Terror of Death. Add onto this the years in R:2, and he has the higher gaming experience. A good deal of Kirito's experience in SAO comes from his betatesting, which doesn't quite crossover, but isn't a definite loss to his own gaming skill. It is fair to say, though, he has less than Haseo has.

Moving onto Kirito's IRL skill, SAO, unlike the world, takes into consideration some of the IRL abilities of the character (the pat test done before playing and so on and so forth). Also, remember that SAO used purely mental commands to perform, whereas R:2 uses some facial aspects (and possibly mental input; there isn't exactly a full explanation), but it also utilizes a highly sophisticated gaming controller for computers. That means that yes, Kirito has a clear reaction speed advantage, but he also has to mentally tell himself how to react whereas Haseo can rely on different button combinations and weapons and still have similar speed overall.

Correction: Kirito doesn't mentally tell the character in-game how to react, in essence its his body. Nervegear literally blocks the signals of the brain to the body and redirects it to the avatar. So the only hindrance would be shitty internet which I doubt our arena would have. We can't have lag on our fight now can we?

Anyway, even with that said I agree that both have similar speed or at least very very close. Even with Kirito's reaction time advantage, Haseo still has the flexibility of multiple weapons in addition to his usual speed.

Specialization/Reaction Time -+=+- Jack-Of-All-Trades/Speed
----Kirito--------------------------------------------Haseo-----------

Now then, did Haseo have sex yet? Nah. Kirito WINS.

BWHAHHHAAHRHAASHDAFHSAD

Okay, that aside we can assume that both characters would know that the battle in melee would just never end. They're nearly on par with each other and they will realize it as they have a go. So do we assume they begin to use their specials? Skeith for Haseo and the all-powerful-Kayaba-access for Kirito.

Now then, if we do see Kirito use Kayaba-access, he could ensure to himself to not feel pain, have extra high speed [like how Kayaba or Heathcliff dodged Kirito's attack at the last moment], or grant himself immortal status but Skeith can still easily break through that with Data Drain.

Can I get clarification? Is this Awakening or simply summoning?
[spoiler=][/spoiler]

In response to your edit, ErrorBlender, that is Summoning. That is the "armor" that appears around Epitaph Uses as they manipulate their Epitaph, each one having a unique design and pattern that represents their Morganna Phase. As mentioned, Haseo has Skeith, the Terror of Death and the First Phase. Here is Skeith's appearance, so you can better understand the design around Haseo:



For the purposes of competition, though, Skeith is in his upgraded form: