This subclass is very versatile thematically, your seirei could be anything tied to the damage type you choose. It could be an angry spirit from the shadowfell that deals psychic damage, it could be a bestial spirit that deals piercing damage or any kind of elemental. It could also be tied to the setting you're playing in, for example, a tiny construct from Eberron, or concentrated dunamis from Wildemount. Talk with your DM to pinpoint who and what your spirit is, where it comes from and how it interacts with your character's theme and personality.

Planar Spirit

When you gain this feature at 3rd level, choose a damage type from the "Damage Types" list (PHB, 196). This will determine the nature and damage type associated with the seirei that will join you for the rest of your journey. As a bonus action, you can spend 2 ki points to manifest the seirei in your space. The spirit is a tiny, small or medium (your choice) magical entity that can occupy the same space as you. You determine the seirei’s appearance. On your turn, you can mentally command your seirei to move up to 30ft in any direction (no action required). If your seirei is ever more than 15ft away from you at the end of your turn, it teleports back to your space. The seirei has an AC equal to yours. If the seirei is ever targeted by a damaging effect or hit by an attack while outside your space, it instantly teleports back to it. Your Seirei counts as a spell for the purposes of Dispel Magic and the Spell Level is equal to half your Monk level (rounded up, to a maximum of a 9th level Spell). The spirit lasts until you finish a short or long rest, until it is dispelled, or until you dismiss it as a bonus action. When you manifest you Seirei, you gain the following benefits:

• When you make a melee attack, any of your attacks can originate from you or your seirei. When you make an attack from the Seirei, all the damage dealt by it is of the Seirei's type.
• Once per turn, you can deal an extra 1d4 damage of the Seirei's type to one creature you hit with a melee attack made with a monk weapon or unarmed strike. This damage increases as you gain monk levels, as shown in the Martial arts column of the monk table.
• If you hit a creature with one of the attacks granted by your flurry of blows, you can deal this feature's extra damage a second time.
• When a creature that you can see within 5 feet of your echo moves at least 5 feet away from it, you can use your reaction to make an opportunity attack against that creature as if you were in the echo’s space.

Acid Seirei

Your Seirei's damage type is acid

Bludgeoning Seirei

Your Seirei's damage type is bludgeoning

Planar Attunement

At 6th level, your connection to your spirit's nature has deepened. You gain resistance to your seirei's damage type. In addition, your attacks ignore resistance to your seirei's damage type. When you reach 17th level in this class, your attacks ignore immunity to your seirei's damage type.

Acid Resistance (Seirei)

Acid Resistance (Seirei)

Planar Awareness

Also at 6th level, your Seirei can aid your senses and help you gain some foresight into events to come. When your Seirei is manifested, you can cast the Detect Magic and Augury spells once. Once you use this feature, you can't do so again until the next time you manifest your Seirei

Planar Protector

At 11th level, your spirit can protect you or your allies from harm. When you or a creature you can see within 30ft of your seirei takes damage, you can use your reaction to send the spirit to their aid. The target then gains resistance to the triggering damage and your spirit disappears. If the damage is the same as your seirei's type, the target gains immunity instead.

Planar Empowerment

At 17th level, your connection to your planar companion has reached its peak, allowing you to bolster each other's power beyond your normal limits. When you manifest your spirit, you can spend extra ki points to empower it and yourself. For every 3 extra ki points you spend, the extra damage granted from Planar Spirit increases by one Martial arts die. You can spend a maximum of 11 ki points when you use Planar Spirit, increasing its damage as shown in the Planar Empowerment table.

 

PONER BONITA LA TABLA DE PLANAR EMPOWERMENT