Ratcatcher

Ratcatcher rogues are those that have learned to enlist vermin and other nasty creatures in their scoundrel arts. Ratcatcher thieves might have their rat friends carry out a night time heist, as if an every day creature skulking about valuable stores. Cutpurses may train weasels to abscond with coin while the rogue awaits some distance off, an alibi in hand. Even more vile, an assassin might sick an angry badger on a target, to dispose of—and digest—the body. Ratcatchers are ingenious, and heinous, their critter friends perhaps even more so.

Vile Charmer

When you choose this archetype at 3rd level, you gain proficiency in the Animal Handling and Nature skills.

Heinous Companion

At 3rd level, you gain a beast companion that accompanies you on your adventures and is trained to fight alongside you. Choose a beast that is no larger than Tiny and that has a challenge rating of 0. Add your proficiency bonus to the beast’s AC, attack rolls, and damage rolls, as well as to any saving throws and skills it, or you are proficient in. Its hit point maximum equals the hit point number in its stat block or four times your rogue level, whichever is higher. Like any creature, it can spend Hit Dice during a short rest to regain hit points.

The beast obeys your commands as best as it can. It takes its turn on your initiative, though it doesn’t take an action unless you command it to. On your turn, you can verbally command the beast where to move (no action required by you). You may command the beast to use Sneak Attack as your once per turn limit as granted by your rogue class.

You can use your action to verbally command it to take the following actions:

• Attack
• Dash
• Disengage
• Dodge
• Help 
• Search
• [Tooltip Not Found]
• Climb Onto A Bigger Creature

If you are incapacitated or absent, the beast acts on its own, focusing on protecting you and itself. The beast never requires your command to use its reaction, such as when making an opportunity attack.

If the beast dies, you can obtain a new companion by spending 8 hours magically bonding with a beast that isn’t hostile to you and that meets the requirements.

Convoke the Horde

Starting at 9th level, you can use the bonus action granted by your Cunning Action to summon a swarm of your beast companions. Use the following rules to generate your beast horde.

• The swarm is considered a Medium swarm of Tiny beasts for size. It's speed is adjusted to 30 ft., unless it is already higher.
• Roll your Sneak Attack dice to determine the amount of beasts in the horde (minimum of three). This does NOT count against your Sneak Attack action.
• Its armor class stays the same as your beast companion.
• Its hit points are determined by the value rolled by your Sneak Attack die, plus the number of dice rolled. For example, if you roll a value of fifteen with your five Sneak Attack dice for this purpose, the hit points for your swarm would equal 20 (15 + 5).
• The swarm's Strength ability score is doubled, it's Constitution score goes up by your CON modifier. All other scores remain the same.
• As with all swarms, it gains the following resistances: 
  Damage Resistances: Bludgeoning, Piercing, Slashing
  Condition Immunities: Charmed, Frightened, Grappled, 
  Paralyzed, Petrified, Prone, Restrained, Stunned
• Your swarm also gains the following feature: 
  Swarm. The swarm can occupy another creature’s space and vice versa, and the swarm can move through any opening large enough for a Tiny creature. The swarm can’t regain hit points or gain temporary hit points.
• All other abilities and actions remain the same.

Clever Little Critters

At 13th level, the rapport between you and your beast companion has deepened even further. You can use your action to verbally command it to take the following the Hide, or Disarm action. Your intimacy with your companion means that if the beast dies, you now only need 1 hour to obtain a new companion of the same kind.

In addition, You may use your Animal Handling skill for any non-combat skill check involving your beast companion.

Your beast companion swarms have advantage on all checks when trying to grapple a creature, or knock it prone.

Writhing Mass

Once per long rest, as an action, you can summon your beast companion swarm by casting the Fear using only vocal components.

Your swarm gathers, filling the space in front of you with countless writhing vermin. Each creature in a 30-foot cone must succeed on a Wisdom saving throw or drop whatever it is holding and become frightened for the duration. If any creatures succeed their Wisdom save, the space occupied by the swarm is still considered rough terrain for the duration of the spell.

While frightened by this spell, a creature must take the Dash action and move away from you by the safest available route on each of its turns, unless there is nowhere to move. If the creature ends its turn in a location where it doesn't have line of sight to you, the creature can make a Wisdom saving throw. On a successful save, the spell ends for that creature.