Tenma

Tenma is a Dakhan, a race of demons which can take the shape of any member of any race. Tenma chose to take the shape of a Saiyan and gained many Saiyan traits and abilities, he also slightly modeled his look after Goku. He is permanently a Super Saiyan 4 and cannot go back to his base form, he became like this upon first taking the shape of a Saiyan. His true form is unknown.

About
All that is known of Tenma is that he was born in the, a land of red mist and clouds, in a dimension in Other World separate from Heaven and Hell. He had two brothers, but its unknown what happened to them. He currently resides on Earth, observing its inhabitants and looking for fighters that he can "take the shape of".

Fighting Ares
Leogian was in his house playing Devil May Cry 3 when a storm happened. He went outside and saw Tenma sleeping in the treetops of the woods by his house, who was manipulating the storm. Tenma woke up when Leogian asked whom he was, so they introduced their selves. Then, a mysterious teenage boy appeared, who said his name was "Ares". Ares taunted Tenma and they fought.

A tornado blew away Leogian's house and the tornado blew Tenma and Ares far away. Tenma was able to power up to a Legendary Super Saiyan 5 (which was not his full power). They were equal but Ares was actually holding back. Tenma demanded Ares show him his full power, threatening to kill an innocent bystander, a 2 year old girl nearby. But Tenma said it wasn't "worth his time" and let the girl go safely.

They fought in space and when Ares wouldn't show Tenma his full power, the enraged Tenma told Ares "Screw you, human!" and created a giant hand of energy, giving Ares the middle finger. The hand exploded and Tenma disappeared.

Slowdown
Tenma can slow down time, making an enemies attack slower and giving him time to dodge. This is useful against people who can attack very fast, at lightspeed levels. However, it can be hard to control and he can only slow down the ones faster than lightspeed a little, but giving him enough time to dodge or teleport.

Gravity Manipulation
Tenma can make gravity heavier or lighter, but he can't use this in space.

Dimensional Intangibility
When Tenma goes intangible, he can shift between dimensions. Some attacks can affect intangible people, but if no one can use dimensional intangibility like Tenma, then they cannot affect him when he does this. Tenma uses this ability to avoid attacks.

Weather Manipulation
Tenma can make it rain and cause thunderstorms, he can also manipulate lightning.

Regeneration
If Tenma is decapitated or loses a limb, he can regenerate it like it was nothing.

Possession
Tenma can possess the bodies of others.

Ki
Tenma can use ki to fly and fire ki blasts, like many people.

Age Manipulation
If you are hit by his Age Manipulation beam, which takes the shape of a flashing comet with white and grey lights (white representing youth and grey representing old age) you can become either younger or older, by Tenma's choice. It is temporary though, not permanent. If you become a child or elderly person, this gives Tenma an advantage over you.

Rift Prison
Tenma can unlock a rift in dimensions which can suck his opponents into it, imprisoning them. He can cause the dimension to explode and blast the opponent out, causing damage.

Giant Pistols
Tenma can create two giant pistols, weighting many tons and standing at about 100 feet tall. He can fire these at will, causing damage to the opponent.