There are 4 towers associated with Flame Leviathan and each one adds something new to the fight in addition to increasing Flame's health. Each tower gives him 50% more health! You must speak to Lore Keeper of Norgannon in order to have the option to keep towers. This achievement is the third level or tier of the hard-mode associated with Flame Leviathan, so make sure to leave one of the towers up. Below are the abilities associated with the towers:

• Tower of Storms - Will allow Flame to use Thorim's Hammer and give him the Tower of Storms buff of 25% extra physical damage.
• Tower of Flames - Will allow Flame to use Mimiron's Inferno and give him the Tower of Flames buff of 50% increase in Fire damage. The Inferno spell is an AOE that leaves a circle of fire on the ground. Try to avoid these as much as possible as they do a lot of damage!
• Tower of Frost - Will allow Flame to use Hodir's Fury and give him the Tower of Frost buff that slows players speed by 20%. Hodir's Fury will cause Frost damage and if you stand in the beam long enough, it will encase your vehicle in a tomb of frost. The tomb causes A LOT of damage and can be removed by igniting the Chopper's Tar underneath the target.
• Tower of Nature - Will allow Flame to use Freya's Ward and give him the Tower of Life buff that will reduce Fire damage taken from Flame by 10%. Freya's Ward will summon Writhing Lasher and Ward of Life adds.

As you can see by the list of abilities, that it will take quite a bit of coordination and probably a lot of wiping before you get this achievement. It's not an easy achievement to get, but also not impossible. Leave the three up that you know the best. Work up to it one tower at a time!