Finally got my 6th tonic have 3-70 Kingston and Llianna. My other green 5 stars are Evelyn and Elkanon.
+1 for Kingston, great stat and attack debuff to 3 opponent is best.
+1 Kingston. I had the same dilemma and never regretted choosing Kingston. Lianna hits a bit harder, but the attack debuff is incredibly useful.
I might even put Evelyn next (depending on a lot of other things) since you have your sniper in Kingston.
Sorry forgot to say maxed 5 stars, sounds like Kingston it is.
Evelyn and Kingston are a killer duo. On a good day, they can even take out Aegir tanks.
Kingston, no second thought.