Jim'Baw Lore and etc
Lore:
Jim was born in a world other than that of Runeterra. Where it is is a mystery. How he got to the Void is a mystery. How he survived in the Void is a mystery as well. But what we do know is he somehow found the Void at infancy and made it his home there. He eventually became one with the Void and became two separate entities: Jim, the child with majority of the magic and Baw a giant snake creature with raw power. Together they are Jim'Baw. Eventually he and Baw escaped the Void and landed in Runeterra. And it didn't take long for the Institute of War to find them and ask them to join the League of Legends. At first they rebuked them but then Jim saw Annie and had second thoughts. He instantly fell in love with this little red head and accepted with the deal that he must limit his power and must keep Baw at bay. So Jim charmed him into a small metal version of his former self and the two head into the Institute of War together.
Jim'Baw has more to him than just a human face. He is a Voidling at heart and mind. - Cho'Gath
Abilities:
Baw's Influence: Every 5 spells Jim'Baw gets a boost in his power. His next ability sends out 25% more magic damage.
Void Mush: Jim fires a ball of dark mush at an enemy. The first enemy will be hit with the mush and take 45/55/65/75/85 damage (+ 35% ability power). Also the enemy will be stuck for 2 seconds.
Cost: 40/45/50/55/60 mana
Range: 720
Recharge: 13.4 seconds
Dark Matter: Jim sends out or can place on himself dark matter that raises his health regeneration by (45% health) and gains 3%/4%/5%/6%/7% movement speed for 3.5 seconds.
Cost: 45/55/65/75/85 mana
Range: 1243
Recharge: 20.2 seconds
Nice and Tidy: For a short duration (3 seconds) trapping, slowing, or defense lowering will not work on Jim.
Cost: 30/35/40/45/50 mana
Recharge: 24.6 seconds
Unleash Baw: Jim is able to release Baw into his true form for 65 seconds. While he unleashed Jim rides on his back and gains an additional 25%/30%/35% magic damage and Baw deals the damage for Jim with 300/500/800 hp and 50/70/90 damage (+ 25% ability power not including the bonus). Jim is not invulnerable on Baw's back and can take damage.
Cost: 100/120/140 mana
Recharge: 65.2 seconds
Friends:
Cho'Gath 
Vel'Koz 
Kog'Maw 
Kah'Zaix 
Annie 
Jim is basically a mid laner and support. Any other additional thoughts, suggestions, and questions can be asked below.