Question about Saïx

[Awkward Squid]

For the life of me I can't find anything to answer this question so I'll chance it to see if anyone else knows.

It's explained in KH 3D that the yellow eyes and pointed ears are sure signs that said people are 'becoming' Xehanort in some shape or form. I know Xigbar was onboard with the whole process and seemingly accepts it; but what about Saïx?

In 358/2 Days he and Axel were plotting against Xemnas from the beginning; and Saïx was clearly on Axel's side at the start of the whole operation, yet his eyes were already yellow and his ears were pointed. Why would that be? Was he aware of the 'Xehanortification' process and accepted it only to further convince Xemnas he was loyal?

 

[Saken]

We don't know, but if I were to suggest anything, it would be that the Resucant's sigil is carved on Saix's face.

He might of been one of the first who grew a heart, so Xehanort, seizing the chance, tried for him first, but he put up a fight and that's what left him the scar.
I don't think Saix is evil by his own will.