Eren isn't aware that Yamask could potentially evolve. Luckily, neither does Yamask. Probably. Either way, it and Panzer do fine as just little guys!

Speaking of Panzer, Eren looks down when she comes over. At first, he's confused, since she's here alone.

"You should stick closer to Reiner," he scolds, but he doesn't really mean it. She stays there sat half on his foot for the moment. Yamask still isn't friendly, but it's grown used to both Reiner and Panzer, so it floats closer. For now, it's even quiet, no crying or keening.

Eren does look up then, eyes casting about for…there. At least Reiner isn't far away from his somewhat wayward Pokemon.

"Reiner!" he calls. "I think you lost someone."