This is Blight (Chaotic Good), he is about mid 20's with a pretty happy backstory for his powerset, minus the fact that he was briefly (from 11 to 15 years old so 4 years) under the control of an, as of now, unknown government who were going to use him as a bioweapon for obvious reasons. They failed incidentally because they tried to incite progress by killing his family. This lead to an emotional outburst and the head honcho happened to think that he had Blight under his thumb and one thing lead to another and he fled the facility with the honchos key card and escaped to a forested thicket, carving a trail of death leading to a cave where he sustained himself off insects and pondered the wonders of nature from a distance for many years. He was later discovered by S.A.G.E and inducted with the condition that he find a way to keep his powers in check (see far below) His powerset makes him an active danger to those around him and thus tends to keep a wide berth from other do-gooders. He is firmly a hero but with a chaotic good personality that edges into malice towards those he sees as corrupt. He does not believe in giving villains more than a few chances and will not budge from that belief. Due to his powers he tends to take on solo missions with comms to S.A.G.E for accountability purposes. Due to his powers, other supers are divided on his hero status as he does not eat conventionally and derives his food from life force which causes him to be fairly unpopular. He has limited answers to abiotic abilities other than his superhuman agility, speed, and stamina derived from his ethereal shape shifting and life force absorption. He avoids skin contact with others fervently as even a small touch causes necrosis to living tissue which makes him unpopular even further. He is generally distrusting of others due to his previous exploitation and due to the nature of this abilities and his potential due to his emotional outbursts which amplify his abilities uncontrollably in short spurts.
YOU MAY ASK QUESTIONS IN COMMENTS :) I think he has the potential to be busted if taken very far and his power is really only one in practice and its applications that are many which is why I have five since I wanted to flesh it out thoroughly. He is kind but does have a mean streak if he gets annoyed enough. He does not like the idea of a suit so he just keeps his skin covered for the most part to prevent accidental necrosis on someone. Namely long sleeves, pants, and gloves of some sort especially.