Each of the three arenas has one secret boss. Please check the maps above to see where the location of these bosses are.
Leptfire Keeper Boss - Hunter's Grotto (Green Arena)
Be prepared for what is possibly the most annoying fight of the entire Vateshran Hollows. This boss is a giant fire nix-ox. He will constantly jump between the platforms and force you to use the Grappling Hook to to follow him. What SOMETIMES works as well: Stay on the starter platform and wait for him to come back to you.
He does not deal a lot of damage, just take a step back when he does his fire spin attack and avoid the fire AoEs this leaves on the ground. The most annoying attack is his conal fire scream. As soon as you land on the same platform as him, he will use this attack to immediately stagger you.
This fight is rather easy but can take a lot of time due to all the grappling. He jumps away from you very, VERY quickly, you sometimes won’t even have time to place all your DoTs on him before he jumps away again. If you play a class which uses several ground-based AoE abilities, this can get really tiresome. Prioritize applying single-target DoTs and direct damage attacks while you can.
For beating the Leptfire Keeper you receive the “Empowered Grapple”, which grants you a speed buff when you use the Grappling Hook. This buff can be very useful during the fight against Rahdgarak, the final boss of the Hunter’s Grotto, because the "Empowered Grapple" also automatically interrupts the Reach Channelers during that fight. After beating the Leptfire Keeper, make your way back to the room where you fought the Shade of the Grove.
Xobutar Of His Deep Graces - The Wounding (Blue Arena)
Xobutar is a Xivkyn. If you have ever set foot into the sewers below the Imperial City, you will immediately recognize that he is part of Molag Bal’s Elite troops, he even emits the same creepy sound as his companions roaming the sewers.
Starting the fight will cause Xobutar to port into one of the smaller chambers next to the arena, and a Mimic Xivkyn appears. You can completely ignore the Mimic, as killing it does absolutely nothing and it will just respawn. Just kite it around and avoid its damage until the Wounding portal in the room activates.
Using the Wounding portal will put you into Xobutars chamber where you have 20 seconds to deal as much damage to him as you can. After this period of time, you are ported back into the room with the Mimic. Wait until the portal activates again to get back to Xobutar. This fight is not particularly difficult, but if your damage is low you will need quite a few portal phases to get rid of him. Make sure to get out of his AoEs and if he summons vampiric totems, destroy them, otherwise they will heal him.
Killing Xobutar unlocks a special buff, the “Empowered Teleportation”. Whenever you are inside a Wounding Portal, a Bound Chillfiend will come to your aid. This can be helpful during the fight against the last boss.
Mynar Metron - Brimstone Den (Red Arena)
Mynar Metron is an Iron Atronach. The boss will always stay at the edge of the little island, never set foot on it. Its attacks consist of different fire AoEs that you need to step outside of. Occasionally the atronach moves to a different spot at the platform’s edge, forcing you to recast your groundbased AoE abilities.
The fight is very straightforward, your biggest challenge is the limited amount of space to avoid his attacks. If you feel too limited, you can grab the Brimstone Orb buff to get a bit more space by running into the lava. Pay attention to when the buff runs out though.
Beating this boss grants you the “Empowered Brimstone”, a buff that causes the Brimstone Fortification to deal damage to nearby enemies.
