Aura of Protection. The knight and each ally within 10 feet of it have advantage on saving throws. This trait is suppressed while the knight has the incapacitated condition.
Spellcasting. The knight casts one of the following spells, using Charisma as the spellcasting ability (spell save DC 15):
1/day each: Greater Restoration, Sending, Word of Recall (the prepared sanctuary is the Solar Bastion)
Multiattack. The knight makes three Sunspear attacks.
Sunspear. Melee or Ranged Spell Attack: +8 to hit, reach 5 ft. or range 120 ft., one target. Hit:14 (3d6 + 4) radiant damage, or 21 (5d6 + 4) radiant damage if the target is a Fiend or an Undead.
Solar Flare (Recharge 5–6). The knight unleashes a blaze of brilliant energy that fills a 30-foot-radius sphere centered on the knight. Each creature of the knight's choice in that area must make a DC 15 Dexterity saving throw. On a failed save, a creature takes 22 (4d10) radiant damage and has the blinded condition until the end of its next turn. On a successful save, a creature takes half as much damage only. For the next minute, the affected area is filled with bright light that is sunlight.
Knights of the Solar Bastion are battle-hardened veterans who operate independently across the multiverse. When word reaches the organization that a Deck of Many Things has appeared, the nearest knight investigates, but every knight has the magical means to contact the Solar Bastion's headquarters and request help. Even so, it's rare for knights to work together outside their headquarters.