Top 5 Hardest Bosses in FGO (Ranked)

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No fight in FGO can be considered impossibly difficult, considering victory is only a few Saint Quartz away.

Being a purely single-player game, there’s no detriment on FGO’s part for allowing players to spend premium currency to revive in every fight.

However, this is not the way the game was meant to be played – as those Saint Quartz should be reserved for summons and summons only.

So we’re here to take a look at some of the toughest boss battles in all of FGO that might make you reconsider dipping into your prized stash.


5. Megalos (Agartha)

Megalos (Agartha) Boss in Fate/Grand Order screenshot

Ooh boy, Agartha had some tough boss battles.

One of the most loathed, however, would have to be Megalos.

Megalos is an enraged version of Heracles who has similar traits such as the Berserker class and the Guts ability.

So, how many Guts passives do you need to break through to take down Megalos? Oh, just 12!!

Try surviving an onslaught of Berserker attacks without having the very rare (at the time) Foreigner class to rely on, while simultaneously having to deal huge damage to break his Guts and multiple break bars.

It makes this fight a real slog.

Luckily, you don’t need to proc all 12 Guts passives. And the battle will end after four or so.

Still, I hope you aren’t too disheartened because you’ll be facing Megalos several more times before Agartha concludes.

Have fun!


4. Kiara/Beast III/R (SERAPH)

Kiara/Beast III/R (SERAPH) Boss in Fate/Grand Order screenshot

This boss fight doesn’t take place in FGO’s main storyline, and instead occurs in one of the largest side-story events in FGO history.

After making your way through the C.C.C event, eventually you’ll complete the story and finish up the final node.

However, in the Epilogue there’s one final boss waiting for you.

Kiara comes out in full force here for a brutal battle with multiple break bars and devastating abilities.

What makes this fight so interesting is that the boss can be weakened by purchasing items from the event shop.

However, masochists out there who want to flex their FGO skills can make no purchases and take on Kiara in her ultimate form as intended.

Good luck!


3. Shuten Douji and Raikou (Shimousa)

Shuten Douji and Raikou (Shimousa) Boss in Fate/Grand Order screenshot

Shuten and Raikou are a tag-team battle in Shimousa where you’re forced to include Musashi in your party.

This means where you may have once been able to create an easy team to deal with these two, you’ll now have to do so with one less available party slot.

What makes this fight so tough are the insanely powerful crits you’ll be suffering, as well as an AOE charm that immobilizes most of your Servants.


2. Arjuna Alter (Yugakshetra)

Arjuna Alter (Yugakshetra) Boss in Fate/Grand Order screenshot

Arjuna Alter is yet another incredibly powerful encounter that forces you to take a support Servant into battle (although this support is arguably a lot more useful than Musashi).

That being said, Arjuna is no pushover.

With a permanent debuff immunity and damage buffs upon breaking his break bars, Arjuna is not here to mess around.

He will also unload his devastatingly powerful NP occasionally, one occuring immediately after the second break!

Take all this and couple it with a three-turn ignore invincibility, and this NP is essentially unavoidable (other than tanking it out with Guts).

We hope your backline is just as up to the task as your main squad for this one…


1. Gawain (Camelot)

Gawain (Camelot) Boss in Fate/Grand Order screenshot

FGO’s early storyline is fairly easy to blaze through.

If you rerolled your account for Heracles, then using him and a support Cú Alter can rip through Singularities one through five without issue.

However, problems arise upon reaching the sixth Singularity – Camelot. And more precisely, Gawain.

This is the first brick wall you’ll hit in FGO.

And while boss fights after Gawain are arguably stronger, this fight forces you to change up your strategy immensely.

Gawain is FGO’s way of telling you that Berserkers will not solve all your problems forever. And to succeed in FGO, you’ll need to raise servants of varying classes and make use of their unique abilities.

How many of you even looked at Euryale before this fight?

If you had, you would have realized just how powerful her charm locking is to prevent the main difficulty of this fight (which is Gawain NPing your entire team every 2-3 turns)!

Gawain is a hurdle standing between you and FGO’s late game.

Will you double-down on your Berserker Buster strategy?

Or will you learn the rules of the game and invest in some of your other units?

The choice, Master, is yours.

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Ruel Butler

Ruel is a lover of all things gaming and anime. He lived, worked, and studied in Japan for several years and has written professionally for several companies. His portfolio can be found at