Does the power of the bonded human depend on how close they are to their bonded legendary? And would someone bonded to say Giratina be more powerful than someone bonded to Entai?

surfacage:

Yeah, for example, Spark has access to the most raw power out of the three titan bonded because he’s the closest to his legendary. But if you got equal closeness to your legendary it comes down to the Pokemon.

Say you’re a legendary demon worm who was sent to time out in a timey wimey space bendy dimension, versus a legendary liondog who causes fire and brimstone calamity whenever it sneezes, the Pokemon still follow typing strength/weakness and moves – worm has fire resist so it might take some creative thinking for the Entei bonded to win.