Technically not incest since Umamusume only sees siblings who have the same mother Irl as related to one another.

That being said it's still weird just as Teio and Rudolf or Vodka and Gimlet or Stego and the Golden Bunch.

Technically not incest since Umamusume only sees siblings who have the same mother Irl as related to one another.

It's incest only if the artist explicitly headcanons it as incest.