How does a player get more than one Warlock or Guardian? There seems to be only one of each in each players lord box, along with three angels and an archangel. Sometimes players get more than three angels also. Thanks

I will assume you are playing the valley games edition:
17.1 A Legion may not add an Angel if it presently contains seven characters or if there are no Angels available in the caretaker’s stacks. The colour of Angels have no bearing on play, cravat Angel of any colour may be taken when eligible. Added Angels are placed directly into their Legion’s stack and are also immediately available to be summoned to another Battle (see 15.0).
17.3 Archangel, are Lords acquired when a player’s score attains a multiple of 500. An Archangel is acquired instead of an Angel, not in addition to it. If no Archangel is available from the caretaker’s stacks, the player may take an Angel. The mechanics of acquiring an Archangel are the same as for Angels. Like Angels, Archangels may be summoned into Battle (see 15.0), are returned to the caretaker’s stacks when slain, and may perform Tower Teleportation (see 8.1)
Other than these, the game is limited to the manifest that it came with, 621 pieces.