Because if you overlevel it, it will be too strong.
Level them up.
level them up on your own and slowly
That's impossible -.-'
u cant evolve a Pokemon on level 100
Train your Pokemon to level 100 or just keep it in the daycare for an extremely long time.
you have an awesome team but you're using too many legendaries take latios out and put in a electrical Pokemon or a dark Pokemon because you have 3 Pokemon that are legendaries.
darkrai lv 100,giratina lv100,palkia lv100,heatran lv100,creselia lv100 and salamence lv100.
Mewto lv100 Mew lv100 and Ho-oh lv100
well the way to have lv100 Pokemon without AR is simple....... RASIE IT!
arceus lv100 dialga lv100 palkia lv100 darkrai lv100 giratina lv100 deoxys lv100
In Trading and I know A person who just caught a celebi level 100 without training it. once I also met a Mewtwo level 100.
Yes, that team is extremely good, mostly due to the fact that they are all Level 100s. However, there is a lack of a mixture of Pokemon (e.g., different types of Pokemon, because Palkia and Dialga are pretty much the same thing). Besides the lack of substance (also due to the fact that the team is all starter Pokemon, where other dragon Pokemon could do well, like dragonite, or even Tyranitar), the team is very good.