Heart was recently on team Complexity, but he hasnt resigned his contract. Heart currently lives with Axiom players Choi “CranK” Jae Won, Jun “Miya” Jong Bum, and Kim “Ryung” Dong Won, along with team Acer’s Mun “MMA” Seong Won.
Source – Gamespot
p.s. You can purchase Heart of the Swarm here.