Natural enemies include:
- Zangoose and Seviper
- Durant and Heatmor
- Tinkaton and Corviknight
- Groudon and Kyogre
I'm pretty sure there's way more, but it is hard to recall them all at once.
I figured that the concept of natural enemies could be incorporated into Pixelmon somehow. Some thoughts I had include:
- If a wild Pokemon comes close to a wild Pokemon that it considers to be a rival, they would battle each other.
- If a wild Pokemon and its enemy are in a horde or double battle together, the Pokemon would fight its enemy rather than you.
- If one of your Pokemon is out of their Poke Ball (including if you are riding it but not if you are in a battle) and a nearby wild Pokemon considers it an enemy, it may aggro. In that case, the aggressive Pokemon would rush towards the "enemy" Pokemon you own rather than you, and that Pokemon that the aggressive Pokemon considers to be an enemy would be the Pokemon you send out rather than the Pokemon at the front of your party. Easily avoided by just recalling the Pokemon before the aggressive Pokemon reaches it.
- I feel that any Pokemon you own should be tame, thus they wouldn't target an enemy Pokemon. This avoids you getting dragged into battles if you are in an area with a lot of enemies. Also avoids complications with mounts, other players, or two enemy Pokemon you own.
- Though if you do decide to make them target enemies (possibly with a config setting), it would be the same situation as bullet 2 where that is the Pokemon you lead with rather than the Pokemon at the front of your party.
The JSON files for each species would have an optional section dictating which Pokemon they would attack on sight. Some would consider each other mutual enemies, while others would have a one-way enemy relationship. Zangoose and Seviper would both consider each other enemies, yet Heatmor would attack any Durant but not the other way around.