Monster Warden: Warlock Subclass

The Monster Warden is a Warlock subclass that blends the elements of a Pokémon Trainer with the mystical powers of a Warlock. As a Monster Warden, you form pacts with powerful and unique creatures, using enchanted vessels to summon and command them in battle.

Subclass Features

Expanded Spell List

The Monster Warden lets you choose from an expanded list of spells when you learn a Warlock spell. The following spells are added to the Warlock spell list for you.

• 1st Level: Find Familiar, Beast Bond
• 2nd Level: Find Steed, Warding Bond
• 3rd Level: Conjure Animals, Phantom Steed
• 4th Level: Conjure Woodland Beings, Guardian of Nature
• 5th Level: Commune with Nature, Wrath of Nature

Monster Vessel

At 1st level, you gain the ability to create a Monster Vessel. This can be any object that can reasonably contain a creature, such as a gem, a locket, a ring, or even a specially enchanted item of your choice. When you form a pact with a creature, you bind it to this vessel. You can summon the creature from the vessel to fight alongside you or perform tasks.

• Binding Ritual: Performing the binding ritual takes 1 hour and can be done during a short or long rest. The creature remains bound to the vessel until dismissed or killed.
• Summoning: You can use an action to summon the bound creature from the vessel. The creature appears in an unoccupied space within 30 feet of you.
• Recall: As a bonus action, you can recall the creature back into the vessel.

Capturing Monsters

Starting at 1st level, you gain the ability to capture creatures to bind them to your Monster Vessel.

• Capture Attempt: As an action, you can use your Monster Vessel to attempt to capture a creature that you can see within 30 feet. The creature must make a Wisdom saving throw against your spell save DC. On a failed save, the creature is pulled into the vessel and is bound to it. The creature must be of a CR equal to or lower than half your Warlock level (rounded up).
• Conditions: A creature must be at or below half its maximum hit points for you to attempt to capture it. You cannot have more creatures bound than your Charisma modifier (minimum of 1).

Enhanced Bond

Starting at 6th level, your bond with your creature deepens, allowing you to share senses and abilities.

• Shared Senses: As an action, you can see through your creature's eyes and hear what it hears until the start of your next turn, gaining the benefits of any special senses that the creature has. During this time, you are deaf and blind with regard to your own senses.
• Empowered Creature: The bound creature gains temporary hit points equal to your Warlock level when summoned. Additionally, it adds your proficiency bonus to its attack rolls and saving throws.

Commanding Presence

At 10th level, your presence commands respect and fear among creatures.

• Aura of Command: When you summon your bound creature, all hostile creatures within 30 feet of it must make a Wisdom saving throw against your spell save DC or be frightened until the end of your next turn.
• Bolstering Aura: Allies within 30 feet of your bound creature gain advantage on saving throws against being frightened.

Master of Monsters

Starting at 14th level, you can bind and summon more powerful creatures.

• Greater Binding: You can bind creatures of CR 5 or lower. Additionally, you can bind up to three creatures at a time, though you can only have one creature summoned at a time.
• Quick Summon: When you roll initiative and aren’t surprised, you can summon your bound creature as part of your initiative roll.

This subclass combines the strategic creature management of a Pokémon Trainer with the mystical and eldritch powers of a Warlock, allowing for a unique and engaging playstyle. The addition of the capturing mechanic adds an exciting and dynamic element to gameplay, enabling you to collect and utilize a variety of creatures in your adventures.

The first level Conditions portion says that you can have up to your Charisma mod of captured creatures (presumably, up to 5). However, your capstone ability says you can bind up to three creatures at a time. Is that supposed to mean you can throw three (non)pokeballs at the same time? That doesn't seem a very powerful ability, as mostly you'll be capturing and keeping creatures I would imagine. 

Also, this is a fun idea but it gets a little....awkward, when paired with the base Warlock at times. A good amount of these abilities follow exactly the structure of the Pact of the Chain warlock, just with a stronger creature. It almost makes me think that this would be better served as a new type of Pact, or maybe a series of Invocations instead of a whole subclass.

Last thing to mention: summoning your captured creatures and then using your spells to ALSO cast a spell like Conjure Woodland Beings would probably make every DM at the table throw their hands up in frustration. The game isn't built around a single character dominating the action economy to the point that they get to dictate more actions than double all of their allies combined.  

Fun ideas, but I think some reworking is needed - just my two cents.