Relics change the math
Relics are permanent bonuses for the run. The ones you grab in act one ripple through every later fight.
Some relics hand you more energy or extra draws. Those help no matter how your deck looks.
Flexible beats niche
A relic that rewards a style you are not playing is a dead pickup. Take it only if your plan already matches.
Relics that smooth the early game are safe. They ease the acts where your deck is still weak.
Read before you grab
Boss relics force a choice between two options. Pick the one that fits the deck you are building, not the one that sounds grand.
Treasure and shop relics cost nothing but attention. Check the relic index before a long run.
Next: The relic index.