Here's why:
* Digimon World Dawn and Dusk have different Digimon lines: Each game features a unique set of Digimon that can be obtained and digivolved.
* Exveemon and Stingmon are Dusk-exclusive: These Digimon are not present in Digimon World Dawn's Digimon pool.
To obtain Exveemon and Stingmon, you'll need to play Digimon World Dusk.
In that game, you can obtain them through:
* Exveemon: Digivolving Veemon with high training in Speed and Intelligence, and either a high or low training in Courage.
* Stingmon: Digivolving Stingmon with high training in Speed and Intelligence, and either a high or low training in Courage.
If you're interested in these Digimon, you'll need to consider playing Digimon World Dusk.