Nothing is known about his appearance since he has yet to make an appearance.
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 present age, 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.