So, I've decided to start a series of Vs. polls because of reasons. I'll try to make matchups relatively fair, and each time will be pulling each character from a different universe so there's no chances of them being heard of beforehand to have strategies against one another. So, this time's contestants are the following:
Wither

Rex Salazar

Wither

Rex Salazar

Now, to list stats:
Wither:
Powers:
-Withering Touch: Wither causes any organic matter he touches to wither away. Organic means that at some point in time it was alive to some extent, so objects such as cotton clothing is affected as well. The way this ability works, it breaks down the forces binding organic material together, putting it to a more base form such (elements). This usually results in a pile of dust where the organic material used to be. This power actually craves being used, forcing Wither to use it quite often.
-Vampirism: Though no actual boosts in ability have been noted with vampirism, it does give him a scary face from time to time, and is implied to give him immortality (in the form of eternal youth). For battle sake, we'll also say it gives him superhuman strength and durability.
Abilities:
-No additional abilities.
Weaknesses:
-His Withering Touch is a passive ability that he has no control over. If he touches something organic, it is going to begin withering.
-Despite being a vampire, he can still be killed.
Personality:
A loner and outcast, Wither has deep set issues regarding his abilities, which are only somewhat removed when he becomes an apprentice to the Black Witch. He's grown to have no issue with killing others, and has a deep set anger against the world. He's fiercely loyal to his comrades, however, this doesn't mean there's no tension between them. His only true loyalty, and likely love, is to the Black Witch.
Rex Salazar:
Powers:
-Technopathy: Rex is able to communicate and manipulate different machines through his nanobots.
-Machine Generation: Rex is able to manipulate the nanobots that are bonded with him to form different robotic parts from his body. This includes but is not limited to: Giant Robotic Fists, A Big Fat Sword, Giant Robot Feet, and a Hoverbike.
-Enhanced Body: The presence of nanobots in his body (his in particular, not all) give Rex increased strength and durability compared to a normal human's.
-Enhanced Regeneration: Rex's nanobots automatically react to threats to his body, and work to prevent serious harm/death to Rex. While not extremely fast, they do tend to be effective, saving his life on multiple occasions.
-Unlimited Nanite Production: The presence of a special nanobot, known as the Omega-1 Nanite, allows Rex to produce a limitless number of nanobots through a self-replication process.
Abilities:
-High Intellect: Rex, despite being a goof, is highly intelligent, able to calculate advanced math problems in little time.
-High Acrobatics: Rex's reflexes and acrobatic talent exceeds that of a normal human's substantially, which is likely due to the presence of the Omega-1 Nanite.
-Combat Training: Rex has received training in both hand-to-hand as well as weapon training due to his working for Providence.
Weaknesses:
-Rex's nanobots are merged with him on a molecular level, so it can be assumed that the machines he generates are organic in nature.
-Despite his intelligence, Rex is a cocky goofball and often gets into disadvantageous situations due to it.
-Rex is able to use only one machine at a time, meaning he has to break down any machines he's currently using in order to use another.
Personality:
Overconfident, reckless, rebellious, headstrong, "smash first, think later," and easily annoyed. He's not sure how he feels about his position with Providence, his employers and overseers, but at the same time he is deeply loyal. He has a righteous attitude, wanting to remain on the side of what he sees as just, but sometimes he can't always be the hero he tries to be.
Battle Location and Conditions:
The location of the battle is the abandoned ruins of city, giving no definitive advantage to either side. The battle does not have to result in death, and can simply result in one side being unable to continue fighting. However, there is a high chance of battle resulting in death.