Kaizene is a 17 year old jonin of konoha(aka the leaf village) He has long black hair
Kaizene was born from itachi uchiha and his girlfriend before the uchiha ,massacre kaizene was always 2nd best in the ninja academy next to ichato saratobi,at a young age he was bullied by ichato and they had several battles alongside their friends,kaizenes sharingan awoke after his friend was fataly injured after being hit by ichato's incomplete rasengan,kaizene then proceeded to pummel itchato until near death because of the sharingans ability to track high speed movement.6 years later konaha was attacked by the two tailed monster cat,and soon it was sealed in kaizene voluntarily. Ichato went missing to look for a taled beast of his own,and came back as the jinchuriki of the three tailed turtle.
He focuses on the strength of his attacks rather then speed,he masters the fire style:phoenix flower jutsu and sharingan,he also posseses fire style:spiral chakra sphere.He has 3 jinchuriki stages,initial,one tailed,and full two tails.He is very powerful shinobi,able to beat hijou hyuga without trying or using his most powerful jutsu.
Initial stage This stage increases his power 3 fold,it increases his speed greatly,his canine teeth grow and his nails grow into claws and has slitted pupil yellow eyes. Sharingan initial He can now track fast movements and posseses red eyes with the typical three tomeo(see sharingan pictures on google) and has increased power and speed. One tail A blue chakra aura forms around his body resembling a cat silhouette his canines grow and his nails grow into claws,he forms a black outline around his eyes. Full two tails. He transforms into a giant blue cat that can use a concentrated beam of pure chakra energy and a fire version.he has sufficient power to destroy a country.