3rd seal of Laevatein and unsealed Laevatein

A sealed burning sword that had originally been the heat source of a lava river in the Ruins. It is said to be a shard of a sword once wielded by the "endwatchers" of the Ruins, holding their immense power within despite its fragmentation. It's a fickle relic that can't be properly wielded by most and usually stays sealed for safekeeping and the protection of those around it. Though if powerful enough, in desperation the seals can be unwrapped to wield the full power of the blade.

The wielder of the weapon can only unpack one seal once per turn. When unsealed, the weapon can be resealed as long as the the wielder has access to the seals or can recreate them, to reseal the weapon the wielder must take 1 minute for every seal to reattach them to the blade. 

The 3rd seal is a smaller more sword like seal that barley contains the unyielding heat of the Laevatein, the weapon is more akin to a blade now and acts as a longsword. The weapon deals an extra 2d6 fire damage to any target it hits.

At level 15, the wielder gains the power to unpack the 3rd seal of the weapon. When the 2nd seal is unpacked and the wielder make a successful attack with this weapon, the wielder can choose to use their bonus action to unseal the weapon during the attack. The target of the wielder's attack takes an additional 1d6 piercing + 1d4 fire damage as the seal punctures them mid swing. The target must make a DC 8 + the wielder's Proficiency bonus Constitution saving throw, on a failed save the seal embeds in the target dealing 1d6 fire damage at the start of their turn until it is removed. The target can use their bonus action to remove the seal from their body.

The Laevatein now unbounded is a blade almost akin to pure lava, releasing an unrelenting sweltering heat. The weapon deals an extra 2d10 fire damage to any target it hits. Any creature within a 20 foot radius for the first time on a turn or starts its turn there, it is burned by the immense heat radiating off the blade, and it must make a Constitution saving throw. It takes 4d4 fire damage on a failed save, or half as much damage on a successful one. The wielder of the Laevatein makes this saving throw with advantage.

If the wielder is attuned to this weapon they gain the following benefits:

• You have immunity to fire damage
• You can unpack the seals of the blade despite your level.
• You can unpack all of the seals in one attack rather than one seal per turn.
• You add a +10 to attack rolls with this weapon
• When the blade is unsealed you can cause those in a 20 foot radius to take the burn damage as a bonus action.

Proficiency with a Longsword allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Damage: Fire, Damage: Fire, Damage: Fire, Damage: Fire, Have the ability to properly wield the weapon (You do not have the ability), Damage, Versatile, Sap