Is this a glitch or something else?

Question

I tried to catch Kyogre with all 3 types of poke-balls I had: Ultra, Premier, Regular. Each time, it didn't work. Is it a glitch or is Kyogre just strong?

Comments

It was all the way down to lowest HP?
...According to our lovely Pokemon Database here it's quite hard to catch.

Answer 1

Kyogre is just strong. The only way a Pokeball is guaranteed to work is if it's a Dream Ball, a Cherish Ball, or a Master Ball. Kyogre could be sleeping and at exactly one hp and still break out of an Ultra Ball. It's all up to the RNG.