If I lose any battles in the Ultra Tier, will I lose a rank?

Question

Since Rank 10 is the only rank in the Battle Tower's Ultra tier and losing doesn't cost you a tier, how does that work?

Answer 1

Unlike the online Battle Stadium ladder, once the player has obtained a rank and/or tier in the Battle Tower, it can never decrease.

Source

Therefore, losing in the Ultra Tier will not drop your rank.

Hope I helped!