I really love the idea of therapy or service Pokémon, I have two questions on the subject! Could tyranitar be a service or therapy Pokémon? If a trainer was just that attached to it and wouldn't accept anything else, could they make it work? Also, if someone's therapy/service pokemon was an eevee, would eevee evolve into the evolution that best suited its trainer's needs?
Tyranitar is not a recommended service pokemon due to its size and the difficulty it tends to have in public. However, because pokemon are so responsive to training, have such a wide range of abilities and can form such strong bonds with their trainer, pretty much any pokemon can become a service pokemon!
If someone was very attached to a Tyranitar and it was well trained, it could receive service pokemon certification.
As for eevee: it depends! That’s the choice of the eevee and trainer what it should evolve into, but a trainer’s needs are definitely taken into consideration. Sylveon is especially desired as a service pokemon for its sensitivity and ability to hold onto its trainer with its ribbons. Umbreons are very good at signalling and crowd control. Flareon’s body heat and soft fur are desired for pain relief and comfort.
