Farming ability aside I think Tarkin, Royal Guard, Vader, MagTroop, and I guess Snowtrooper. I really feel like Empire is missing one or two characters from really being good. Snowtrooper and Veers both get a nice speed boost from Tarkin and they both gain turn meter on an opponent toon's death, so potentially you could get a downhill snowball effect where they just build steam. RG's stun... Maybe. But then there's the whole farming thing, how do you get Tarkin and SnowTrooper up? LOL