So I built Keaton differently and I really found it to be something not to underestimate.

I wanted to focus on his enemy phase melee matchups, so I gave him steady stance 3 (budget build). Sacred seal could be quick riposte, but if he has at least 2 infantry pulses or 1 infantry pulse and he holds quickened pulse, he has no need for it. I brought this build to Arena Assault at high scores and he crushes armored units until the level of Brave Hectors with a 50+ damage Ignis.