Lore: Enslaved by the Zerg as a young child, BioTron was engineered to be intellectually intact as an Aberration, but bound by emotional attachment to his parent Overmind. By keeping the infected mentally intact, the Aberration is capable of leading the pack in battle, and enacting strategic maneuvers that would have otherwise been impossible for the mindless swarm.
Bio is a tanky caster with a unique minion mechanic. He also arguably offers the strongest control over Aeon and Daggoth - with his ult offering insane damage potential - especially on stationary targets. Max Claymore first - and it is frequently worth it to wait after burrowing for the cooldown to refresh so you can immediately use the skill again after poping. Run 0/2/4 talents, grabing health, armor, cooldown reduction, energy regen, swiftness, and transport.