An opponent cannot block and kill enough of your creatures to end the combo.
Steps
At the beginning of combat, Helm of the Host and Brudiclad trigger.
Resolve Helm of the Host's trigger, creating a nonlegendary copy of Najeela with haste.
Resolve Brudiclad's trigger, creating a token, then causing all tokens you control to become copies of the nonlegendary Najeela token with haste.
Attack with at least three Najeela creatures.
Each Najeela triggers at least three times each, creating a total of at least nine Warrior tokens that are tapped and attacking.
Activate Phyrexian Altar at least five times by sacrificing at least five Warrior tokens, adding at least ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) .
Pay ({W} magic symbol) ({U} magic symbol) ({B} magic symbol) ({R} magic symbol) ({G} magic symbol) to activate any Najeela, untapping all attacking creatures, giving them trample, lifelink, and haste until end of turn, and creating an additional combat phase after this one.
Deal combat damage, gaining life equal to the amount of damage dealt.