Nothing is known about his appearance since he has yet to make an appearance.
On his sketch, he is shown to have shoulder-length hair that appears to be slimey. He has a long jawline and a pointy chin. Toxic Chainsaw is very well-built and muscular, he also has an outie belly botton.
Toxic Chainsaw is depicted as topless in the sketch. He wears baggy pants with skull-shaped kneepads and army boots.
Nothing is known about his personality. However, since he is a villain and seeing the reaction of someone who is knowledgeable about heroes and villains, it is most likely that he was ruthless and cruel, as he is still feared now.
Five years before the start of the series, Toxic Chainsaw fought against All Might. It is unknown what became of him afterward, but his name still lives on in infamy, as shown when Izuku Midoriya asks if he was the one who gave All Might the scar on his chest. All Might denies it was him, though.
Nothing is known of Toxic Chainsaw's abilities, though, it is possible that he is quite powerful, as Izuku considered the possibility that he could have been the one who injured All Might. All Might himself even acknowledge that Toxic Chainsaw was fairly powerful, able to get a few hits on the Number One Hero, though still acknowledges he lacked the necessary power to cripple him.
Unknown Quirk: Toxic Chainsaw possesses a Quirk of unknown name and unknown nature. It is likely very powerful, given that Izuku believed he could have been the one to injure All Might.
In the sketch, he was shown to wield a chainsaw, befitting his name.