Crisipo

Crisipo, a male, is a minor character in Nanu's Revenge. He is Hapu's second known Pokémon.

Description
He resembles [Argenta]], but is golden in colour. His feathers, crest, edge of tail fin and the scales on his fin are all light golden in colour, his mask and tip of crest a darker golden colour, while his ears, eyes, and nostrils ocean green in colour. He is slightly taller than Argenta, with three claws on his front feet instead of four.

Before Nanu's Revenge
In chapter 15, Nanu has a dream from Argenta's POV, watching Crisipo get shot by a tranquiliser dart, collapsing and dying. However, it is later known that he did that on purpose to pretend he's dead, so he could escape Faba.

In chapter 21, Nanu as well as Naomi, speaks of a Pokémon, being golden in colour, saving Naomi and him from a. It was unknown whether or not to them if it was Crisipo, but Argenta confirms that it may have been him, which means he is older than Argenta.