What remotely makes you say he is?
He feels a commander's place is on the battlefield, not hiding in an office.
He marches into battle with his forces.
He intentionally and eagerly engages in combat himself and only with whoever seems to be the strongest.
If anyone is too weak, he has no interest in them (though that may mean he walks away or he might outright kill them).
He's intentionally wanting rebellion, he wants the people that are subjugated to be so fueled by hate that they'll fight back just so he can crush them again.
He actively wants to be engaged in combat with the strongest he can find.
What makes him a coward? Though I'm only at level 66 closing in on 67. Just met up with Hien.
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There's enough times that we get hit by mortals and get knocked back from the attack. We block it, but we don't stand like a wall. I've never felt the game's given me the impression that I'm nigh a god among mortals, just a vaunted champion of accomplished battles. The only thing that stands out is the echo granted immunity to Primals' control.
One could heap similar praise on a number of our companions outside the Primal factor.
They've made it clear Zenos is unusually strong and shockingly powerful. Like you said, intriguing (and once you're done with Ruby Sea and far enough into the next zone... it gets worse from a story perspective).