Honestly, nailing emotional scenes in stories with Kokichi Oma requires playing into his inherent contradictions. He’s a character built on layers of deception, so any genuine emotional payoff has to feel earned against that backdrop. The key is letting the reader’s perspective be the anchor of reality. From the outside, Kokichi might be teasing, deflecting, or outright lying, but through the reader's internal monologue and physical reactions—a caught breath when his smile falters, the specific weight of his hand when he briefly grasps theirs before pulling away—you can build a subtext of real feeling. His vulnerability should almost never be stated outright by him; it should be something the reader character pieces together from the cracks in his performance, like noticing the slight tremor in his voice after a particularly cruel joke he tells about himself.
I think the setting matters a lot for upping the emotional stakes. Putting him in a situation where his usual tactics of misdirection are physically or socially impossible can force those moments. Maybe he’s injured and too weak to maintain the energetic facade, or perhaps he’s trapped alone with the reader character after a shared traumatic event. The silence or the exhaustion becomes a conduit for emotion where dialogue would usually obscure it. Instead of having him confess anything, you could show him quietly observing the reader character’s care for him, his usual mocking commentary dying on his lips, replaced by a look of bewildered, quiet conflict that the reader can interpret. The emotional weight transfers from what he says to what he doesn’t, and what the reader observes in those gaps.
Finally, the resolution shouldn’t magically fix him. A truly emotional scene with Kokichi might end with him retreating back behind his walls, leaving the reader character (and the audience) to wonder if the connection they glimpsed was real or just another one of his games. That lingering doubt is part of the poignant ache of the dynamic. The last beat could be something small—the reader finding a small, discarded item he left behind, a trinket that contradicts his earlier lie, a tangible piece of evidence that there’s more beneath the Supreme Leader’s cloak.