Basically the short version of this idea is the character has a heritage sword inherited from his father who was a champion to an empire so the sword lore wise is an artifacts by nature and honestly 5th ed kind of sucks in giving fun magical items. However i don't want something stupid broken from the DMG that I simply slim down for a lv 1 to use like trying to bullshit a holy avenger at lv 1. So here are the two write ups for the armor and Sword. I wanted something that was going to offer options but not overwhelming power at least until around lv 17. I wanted those effects to seem powerful and awesome so on those I'm looking for real balance issues on them. For the most part I stuck to slightly re-skinning some spells at around the same level a paladin or cleric would acquire them.  I also have the same thoughts for armor but I'm still working on the details of that and i want to see what opinions are like on this first.

And yes i realize some people are going to take one look and go this gives way to much. I will preface this and counter with the face all these effects are one time use per day and most take a full action to use depending on what level the character currently is. None of which should offer any staggering power boost outside of having a few additional spell options or perks once per day.

Donanu - The Platinum blade of Judgment

• Bastard Sword 1H - 1D10 dmg - Heavy - Versatile (1D12 2 handed)

Donanu was forged by Borkadd the Claw from one of Bahmuts scales and a strange metal that fell from the heavens to be his embodiment of Bahmuts judgment in the ancient dragon empire of Arkhosia. The Blade was always wielded by the HighLord General of Arkhosia and passed down each generation to the next HighLord. The blade is unusually light despite its larger than average length and width of the blade, the metal a shimmering pale blue with veins of gold, silver and black flecked though the folds of the metal. The blade feeds into a dragon pommel, the Golden visage of Borkadd entwines its way up from the sunburst pommel, its wings cupping the base of the blade helping to form the hilt and cross guard of Donanu. The dragon eyes are inlaid with clear sunstone gems that blaze with a internal light that never dims. Just as Borkadd’s vigilance will never waver as Bahamuts hand of justice neither will Donanu’s gaze be blinded. Ten Celestial runes climb the blade. Set within the fuller, each run carefully etched into the metal and filled with the purest Mithril. Each one bestowing a Gift upon the wielder as their power and bond to the blade grow over time. When Drawn an icy aura surrounds the blade, sucking the heat from the nearby area as the runes glow with a pale white radiance. For most it brings a slight chill, to those that hold evil in their hearts it brings a bitter cold that makes their soul shiver in fear because deep down the soul knows its final judgment is upon it.

• Donanu cannot cut or bring harm to any Innocent creature
• If an evil aligned character would hold Donanu, they are encumbered by the weight of their evil deeds made manifest. Should they try to wield Donanu in combat, they take 2d6 cold damage every turn.
• Those who carry Donanu have a fervent zeal to uphold lawful behavior.
• Anyone who carries Donanu for longer than a week has his or her alignment changed to lawful good, lawful neutral or lawful evil depending on there previous alignment.
• Donanu acts as a beacon to any dragon within 100 miles as a powerful divine source of good.
• When Drawn no Lie can be spoken within 30 feet of the Donanu

Donanu scabbard is almost as much of a legend as the blade itself. Made up of scales from both metallic and chromatic dragons as a sign of their unity under the Arkhosia Banner. Its surface shimmers with a inner chromatic radiance whenever the light of the sun hits it. Those who hold it are said to be touched by all the dragons and no mortal wound can be inflected upon its bearer.

• If you posses Donanu’s scabbard you automatically save on any death saving throw. Once used this ability recharges as the dawn of the next day.

Magical Weapon Level

• Lv 5 +1
• Lv 11 +2
• Lv 17 +3

Blade abilities by level

All effects are discharged after use and recharge at dawn the next day.

• Lv 1 - Bahamut’s Grace - An Icy Chill emanates from you, gain residence to all cold damage and +2 on intimidate checks.
• Lv 3 - Judgments Chill - When Drawn the weapon can extinguish all non magical fires within 30ft of you once per hour.
• Lv 5 - Bahamut’s Boon - The icy Chill causes Frost to appear on your armor, Gain Resistance to all fire damage
• Lv 7 - Icy Image - As an action you are surrounded in a icy storm of reflective crystals creating three duplicates of yourself for one minute. Until the spell ends the duplicates move with you and mimic your actions, shifting positions so that its impossible to track which image is real. You can use your action to dismiss the illusory duplicates at any time. Each time a creature targets you with an attack during the storms duration you roll a D20 to determine whether the attack instead targets of of your duplicates. If you have 3 roll a 6 or higher, if 2 roll an 8 or higher with only one you must roll an 11 or higher. A duplicates AC = 10 + Dex, a duplicate can only be destroyed by an attack that hits it, all other damage and effects do not damage it. This spell does not work if a creatures uses blind sight or other sense for seeing along with anyone able to prove illusions as false, as with truesight.
• Lv 9 - As 1 action you sprout draconic wings of platinum and gain a fly speed of 60 for 30 minutes.
• Lv 11 - Icy Mist - Using one action a icy mist rises up from the ground around you for 30 seconds in a 20ft tall and 30ft radius. The fog turns the ground to ice making it difficult terrain. When any evil aligned creature enters teh area for the first time or starts its turn in the effect, it must make a Dex save vs your spell DC or fall prone. If a creature is concentrating inside of the area it must make a spell save vs your spell DC or loose concentration.
• Lv 13 - Your skin is covered in fine Platinum Scales and you gain resistance to non-magical piercing, bludgeoning and slashing damage.
• Lv 15 - Breath of Bahamut - Your lungs fill with the cold judgment of the Platnium dragon, gain the use of the dragon gods breath weapon once per day as an action breath out a 60ft cone breath weapon - Con save vs half 8D8 dmg if killed becomes a frozen statue till thawed.
• Lv 17 - Bahamut’s Radiance - The light of the Platinum Dragons radiance fills you to bursting, unleash his judgment to all those that would oppose you and smite down the wicked. 30ft radius around you Con save for half and to not be blinded. Failed save = 12D6 radiant damage and are blinded for 1 minute. If blinded the creature can make a con save at the end of its turn. Dispels any darkness created by a spell. Evil aligned creatures have disadvantage on the save
• Lv 20 - Avatar of Bahamut - You assume a dragon form of the platinum dragon himself for one hour and gain the fallowing special attacks.
  • You are Large size and gain the benefits of Stoneskin and an icy coating to your scales for Half your total Hp as Temp Hp. Your AC and HP Remain the same.
  • Fly speed of 90ft Breath weapon Cold -30ft cone - 10D6 damage - Recharge on a 6
  • Multi attack - 1 Bite and two claw attacks or one bite and a tail attack. These count as if they were magical weapons.
  • Bite attack Your hit 2D8+str Piercing
  • Claw attack Your hit 2D6+str slashing
  • Tail Attack - Your hit 1D8+str and knocked prone
  • Aura of Fear - 60ft radius Will save vs Your Spell DC or the creature becomes feared and you have advantage against feared targets. If the creature saves they become immune to the aura
  • Immune to cold and Fire damage