The tag implication #64953 undertale_yellow -> undertale_(series) has been rejected.

Reason: The characters and other elements may appear in non-undertale contexts (such as in the deltarune continuity), so this makes more sense then implicating it to undertale.

EDIT: The tag implication undertale_yellow -> undertale_(series) (forum #420521) has been rejected by @spe.

the game is not an official game in the undertale series, it's a fan game

It is better for the tags to remain separate so that people can search for images that have both canon and fanon elements, such as ceroba_ketsukane toriel, clover_(undertale_yellow) frisk_(undertale), or any other arbitrary character combo.

donovan_dmc said:
the game is not an official game in the undertale series, it's a fan game

Huh... today I learned. Always thought it was the official Undertale III.

(In my defense I'm not an Undertale fan.)

The tag implication undertale_yellow -> undertale_(series) (forum #420521) has been rejected by @spe.