Quantumancer (5e Subclass)
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Arcane Tradition: Quantumancy
The robed figure studies the zombies that surround him. He draws his sword, cutting down the first of the undead with a powerful slash, and he is the only one left standing. An elven woman cloaks herself in a living shadow that splits into two, blades slashing out of both veils of mist until the shade is broken. The crafty dwarf cracks his knuckles, then concentrates on his magic and, without so much as a second thought, walks through the solid wall of the dungeon.
In fantasy worlds like the Forgotten Realms, mathematics, sciences, and the arcane are all intertwined. In most cases, this connection is overlooked by mages and scholars, looking mostly towards a specific goal in one area or the other. A Quantumancer focuses on those connections and learns to control various aspects of how the multiverse works, using their arcane abilities to dictate how matter and energy act.
- Quantum Knowledge
Through your studies, you have learned various exploits to the world's probabilities. When you choose this subclass at 2nd level, you can use your INT modifier instead of DEX for armor class, ignoring any limitations that would otherwise apply (you can add your full INT modifer even with medium or heavy armor). Also, once per long rest you can re-roll one skill check made by you or any other creature in a 30ft radius. You may choose to keep either roll, as if it was the original result. At level 6, you can re-roll once per short rest.
- Alternate Feature - Probability Flip
With your DM's approval, you may exchange the Quantum Knowledge feature for this one. When you choose this subclass at 2nd level, you may chose to invert one skill check or attack roll per long rest, subtracting the result of the initial roll out of that die's maximum, usually 20. If multiple dice were rolled, this applies only to the lowest roll. Add any modifiers, unless negative, after the inversion.
Starting at 2nd level, you can choose two beings and magically link them. Once per long rest, you can spend your action to Entangle two beings you can see and roll a d10. Whenever one linked being receives healing or damage, the other takes an amount of the same effect proportional to the d10 roll: 1-3 is no damage, but must make saves for conditions; 4-7 is half damage; 8 or 9 is full damage; and 10 is 150% damage. If either becomes affected by poison or a similar condition, every other linked being must make a Constitution save against your spell save DC or suffer the same condition until it ends on the creature initially inflicted or the entanglement ends. Entanglement lasts until dismissed with an action, one of the linked beings drops to 0hp, you are incapacitated, an abilty that is able to cut the Astral Projection tether is used or the two creatures are not on the same plane anymore. If one of the creatures drops to 0hp, all other linked creatures must make a WIS saving throw against your spell save DC against madness. If the fail, they get one long-term madness effect from the DM Guide. At 11th level you can entangle creatures twice per long rest and at 16th you can do it three times.
Starting at 6th level, difficult terrain no longer affects you, and once per short rest, you may pass through one solid object, wall, floor, or creature no more than 2 feet in width and not magically protected. This may also be done as a reaction in combat to avoid one attack that would otherwise have hit. At 12th level, you can do this twice per short rest, and at 16th level, you can phase through magically protected barriers up to 5 feet in width.
Starting at 10th level, you have learned to abuse the art of teleportation and exist in two places at once. Once per long rest, a black mist shrouds you and splits into two, the second moving up to double your movement away from the original upon its creation. While in this form, both instances can attack at the cost of half damage and can cast spells at half duration, number of targets, and magnitude of effect when applicable. The spell slot cost is not changed. Each instance can move independently, up to your speed in distance, totaled at up to double your movement between the two. You take half damage from ranged attacks and AoE abilities, unless the AoE encompasses both shrouds. This form ends when you take an action to end it, appearing at your choice of the two points, or if a measurement is forced by being observed as an action by a creature with Truesight or a similar ability able to see through illusions, or by being touched in any way, including successful melee attacks against you. If a measurement is forced, roll 1d20 - an even number puts you at the current position of the destination shroud, and an odd number puts you at the current position of the original shroud. If the roll puts you at the location of a melee attack, you take full damage and automatically fail any saving throw it might impose; otherwise, the attack misses. This ability cannot be initiated if being focused on by a creature with Truesight. At 15th level, you can go into superposition once per short rest.
Also, while cloaked and not in focus of Truesight, your body can act as pure energy and attack with the Eldritch Blast cantrip, casting a beam from each shroud. This ability is an exception to the aforementioned spellcasting limitations while in Superposition. This can be done five times per long rest, restoring one use after a short rest. At 15th level, you cast two beams from each shroud.
Starting at 14th level, you've learned how to apply the principles of superposition to life and death. Once per 1d6 days, when reduced down to zero hit points, a black mist shrouds you, and you automatically disengage from your attacker and are moved outside of their melee range. You do not take an attack of opportunity. While in this state, you can move as normal, deal damage at half magnitude and cast spells at half duration, number of targets, and magnitude of effect when applicable. The spell slot cost is not changed. This state ends if you take damage or healing from an outside source, are observed as an action by a creature with Truesight or other abilities able to see through illusions, or 1 minute passes. If you take damage, you are reduced to zero hp and fall unconscious. If you receive healing, the shroud fades away and your HP is restored to the amount it was before taking the blow that initiated Superstasis plus the amount healed for. If the effect ends to time or Truesight, roll a d20, where an even number restores you to the HP you had before taking the blow that initiated Superstasis, and an odd number reduces your HP to zero and you must roll a death saving throw. Superstasis cannot be initiated if being focused on by a creature with Truesight. You cannot enter Superposition while in Superstasis. At level 20, you can do this once every 24 hours.
Thanks to your studies, you gain a new option for your 9th level spell. See chaotic rift.