All of Axew's abilities are good, rivalry may not be the best ability, but it can still come in handy. For example, rivalry deals double the damage when you verse a Pokemon of the same gender.
So, this is a 50% change you have with all Pokemon - except the ones with no gender or who have a definte gender.
If your axew's male, it deals double damge to:
- All various gendered Pokemon who have male
- rufflet and braviary
- hitmonchan, hitmonlee, hitmontop, and tyrogue
- landorus, thundurus, and tornadus
- nidoran male (and it's evolutions)
- sawk and tauros
If your axew's female, it deals double damage to:
- All various gendered Pokemon who have female
- happiny, chansey, and blissey
- flabebe, floette, and florges
- smoochum and jynx
- petilil and lilligant
- vullaby and mandibuzz
- nidoran (female) and its evolutions
For more imformation: search up male, female, or genderless Pokemon (on google)
Hopefully I helped!