Saix is a character from Kingdom Hearts. He's known among a large group of fans as Saix-puppy, where he acts like a dog owned by Demyx. The exact reason for his role as a puppy is only known by the creator(s) and people who the creator(s) have told, but some possibility for this are:
1. His pointed ears
2. His seeming loyalty to Xemnas throughout the game
3.His power of the moon (lunar eclipse) (wolves howl at moon, wolves are dogs...)
ect...
He only acts like a dog when his 'master', Demyx, is around

Noun: a friend who is usually only called upon by a friend when a more primary/prominent friend is unavailable.

Taken from the term “second string” in an athletic competition situation. In football, if the star quarterback gets injured during a play, the second string is called off the bench to replace him/her. A “Second String Friend” is essentially benched until needed, if ever.

Synonyms: Plan B, Second Choice, Secondary Friend, Benched Until Needed