Gordon?
Arceus is not in Explorers of Time or Explorers of Darkness. There is an Arceus statue in Explorers of Sky, but there is no real Arceus that will join your team.
Defeat Darkrai then cresselia will be outside your house talk to her she will join your team.
Defeat him at spacial rift then go back there and beat him a second time he will join your team probably.
It doesn't necessarily join on the first time. On my explorers of time he it didn't but on my explorers of sky it did. It's all to do with Giratina's recruit rate (about 8.6%)
fight him again
Give him an oran berry then attack him and run away later on in the game he will find you and he will join your team
well you have to defeat the Pokemon and sometimes the Pokemon will ask you if it can join your team............................................................................................:):)
In order to get pichu in explorers of time and darkness you MUST graduate from the guild then go to amp plains and eventually you will see a pichu beat it and it may join your team
you defeat them and they just ask to join your team☺
It might join your team if you battle it and win in a mystery dungeon
23 floors. at the end you battle articuno and he may or may not join your team. Actually he will join your team if you battle him a second time but you have to beat him quick and have a high lvl for him to definitly join your team when you battle him a second time.
Go up to Temporal Tower for the second time and defeat him. He will ask to join your team. you need the acion replay