Isekai Guardians how to unlock a guardian: Use a guardian shard from your inventory to unlock that companion permanently, then open the Guardians screen and set it active. Unlocking and activating are two different actions, and only one Guardian is active at a time.
Isekai Guardians how to unlock a guardian, step by step
A guardian shard from your inventory unlocks the companion permanently. The Guardian then sits in your collection, but it does not join you until you set it active yourself, and the one you set active is the one shown on your home screen.
The collection screen lets you inspect companions and read their descriptions without equipping them, so you can compare a new unlock against what you already use before switching. Nothing is lost by leaving it inactive for a day.
Extra shards upgrade the guardian you own
Shards for a guardian you already own are not wasted. Spend matching shards to upgrade that guardian, and the upgrade panel shows the available levels and the improvement each rank gives you.
Open the upgrade preview before confirming, because it lists the number of shards required and what you get for them. That is the difference between putting shards into a companion you use every day and putting them into one you never set active.
Shards arrive in your inventory from summon results, so if you are still short of them the summoning guide covers where they come from and what else those results contain.
The five rarities, and why they are not the decision
The Guardian rarities run Basic, Rare, Mythical, Legendary and Ethereal. Rarity is useful context, and it is not the deciding factor.
Compare the actual bonuses and the stats your build needs before you change your active companion. The bonuses a Guardian carries are Power, Defense, Accuracy and Evasion, so a Mythical companion whose bonuses duplicate what your class already covers can be less useful than a Rare one that covers a gap. Read the numbers on the screen, not the tier colour.
The same advice applies to equipment rarity: consider the item's stats, its level requirements, and whether it supports your equipment set and class before replacing a piece for its rarity alone.
Compare the bonuses, not the rarity
A short practical checklist before you switch:
- Read the Power, Defense, Accuracy and Evasion bonuses on the incoming Guardian.
- Compare them with the bonuses of the Guardian you have active now.
- Check that the bonuses fit the role your gear set already plays, rather than duplicating it.
- Only then look at the rarity tier.
Guardians contribute to the same total as your gear, training and class, so they fill gaps rather than replace them. That is also why the four stats they improve are worth understanding, which the stat guide covers in full.
One last practical note: the character shown on the official Steam screenshots has an active Guardian named Vera — Thunder Songstress, which is the kind of example worth recognising in your own screen when you are hunting for a first companion.