Colen, Lance, Sumi in that order.
Colen is a nice tank and a massterminator in green trials due to his DoT.
The buffs of Lance are less strong as it sounds on the card and he is a bit of a glasscannon. But he is a nice flank supporting the wing.
Do Sumi before Lance if you have multiple sakuras. The mana will charge remarkably faster, if you have at least two more and other sakuras.
The good old Colen is by far the best 4* red. (some would say Boldie, but not in my opinion - he’s second I think)
Take him on wing when raiding or as tank in defense. If he fires, he gives death. In trials and as tank even slow mana will do.