All creatures you control do not have summoning sickness.
Opponents can not block and kill creatures you control.
Steps
Declare
Najeela and four other creature as attackers.
Najeela triggers, creating a 1/1 Warrior creature token that is tapped and attacking.
Druids' Repository triggers five times, putting five charge counters on it.
Activate
Druids' Repository five times by removing five charge counters from it, adding ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) .
Activate
Najeela by paying ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) , untapping all attacking creatures, giving them trample, lifelink, and haste, and gaining an additional combat phase after this one.