Frost Knight

Frost Knight

Icy Bond

At 3rd level, you learn to invoke a rite of Permafrost within your weapon at the cost of your own vitality. granting it extra cold damage. 

As a bonus action, you can activate the rite on a bonded weapon with the elemental energy of ice that lasts for 1 hour, or if you aren’t holding the weapon at the end of your turn. When you activate the rite, you lose a number of hit points equal to two rolls of your Permafrost die, as shown in the Permafrost Die column.

For the duration, attacks from this weapon deal additional 1d4 ice damage. This damage is magical, and increases as you gain levels as a Fighter, as shown in the Permafrost Die column.
-------
Also, 

you learn a ritual that creates a magical bond between yourself and one weapon. You perform the ritual over the course of 1 hour, which can be done during a short rest. The weapon must be within your reach throughout the ritual, at the conclusion of which you touch the weapon and forge the bond.

Once you have bonded a weapon to yourself, you can't be disarmed of that weapon unless you are incapacitated. If it is on the same plane of existence, you can summon that weapon as a bonus action on your turn, causing it to teleport instantly to your hand.

You can have one bonded weapon,  If you attempt to bond with a second weapon, you must break the bond with the first one.

---
Permafrost Die:
Level 3: 1d4
Level 4: 1d4
Level 5: 1d6
Level 6: 1d6
Level 7: 1d6
Level 8: 1d6
Level 9: 1d6
Level 10: 1d6
Level 11: 1d8
Level 12: 1d8
Level 13: 1d8
Level 14: 1d8
Level 15: 1d8
Level 16: 1d8
Level 17: 1d10
Level 18: 1d10
Level 19: 1d10
Level 20: 1d10

Extra Attack

See base class. (only added for bug workaround)

Shiverblade

Starting at 7th level, you may use a Bonus Action to encase your blade in ice. The next successful attack you make with this weapon on this turn, will deal an additional 1d6  cold damage.

You may use this feature a number of times equal to your Charisma modifier per long rest.

At 12th level the extra damage increases to 1d8, 1d10 at level 16, and 2d6 at level 20. 

Frost Skin

At 10th level, you can encase your skin in a layer of ice as a bonus action. You gain +2 to AC, resistance to Cold damage, and Weakness to Fire damage. 

These effects last for 1 minute and are not usable again until you finish a long rest. 

Cold-Hearted

Starting at 15th level, enemies become scared to even hit you, and you become as stubborn as the ice you control. As a reaction to any attack made against you by a creature within 20 feet, you  stare into the attackers soul, Make an Intimidation(Cha) check against their Wisdom score. On a success, that enemy has disadvantage on its attack next turn if it chooses you as a target.

You can use this feature an amount of times equal to your Charisma modifier (minimum 1). You regain uses on a long rest.

Iced Earth

At 18th level, your control over the cold has doomed all that oppose you. As an action, you may swing your weapon in a large arc around your head in a circular motion repeatedly,  creating a blizzard, no matter where you are. This blizzard is special, as it slows all creatures within a 30ft radius by half their speed. And for every turn a creature spends in this blizzard they take  1d10 cold damage. This effect ends after 1 minute.

You may use this feature once per long rest.

This ability requires concentration.