Starting at 6th level, The Outsider’s grants additional gifts to choose from. You can pick an invocation from the following options, provided you meet all other prerequisites. Bonus Invocation options: Beast speech, Devil’s Sight, Ghostly Gaze, Otherworldly Leap, Improved Blink, Otherworldly Athleticism, and Dust to Dust. You can choose another bonus invocation starting at level 10.

At 1st level, The Outsider grants those that bare his mark the ability to propel themselves forward at incredible speed. You can use your Outsider’s Mark, and expend your bonus action, to instantly move 15 feet in any direction to a location within line-of-sight without provoking attacks of opportunity and ignoring difficult terrain. This ability counts against your maximum movement for that turn.

When your marked hand is free you can cast spells granted to you by your Pact of the Outsider class features without components. (This is not compatible with Pact Magic).

At 1st level, the mark is burned into the back of your left or right hand glowing or pulsating when one of the gifts of The Outsider is used. This mark grants the following features:

The Outsider lets you choose from an expanded list of spells when you learm a warlock spell. The following spells are added to the warlock spell list for you.

The Outsider, a mysterious black-eyed humanoid exists in a realm known as the void, where he seemingly holds dominion. He gifts his mark to those he finds interesting, a symbol indistinguishably from a tattoo on the back of the hand. The Outsider is known to visit those who bare his mark in dreams or snap visions to monologue whether this serves as a portent or to merely torment them is unclear. His true goals are as murky as the void, seemingly omniscient he has boasted time and time again, “he sees everything.” It seems he takes great joy in cause and effect, selecting humanoids whose decisions can cause a time of great ruin or placidity. There are a myriad of gifts The Outsider grants, though the ability to blink is among the most common. Often picking those with martial skill it is most common to see Warlocks of this Patron taking up pact of the blade. If you consider taking pact of the chain, ask your DM if your familiar can be a gothic steampunk heart that whispers to you telepathically telling you secrets about those around you.

Pack of Rats

Starting at 6th level, your affinity for rats strengthens. Maybe it’s the plagues rats carry that bring indiscriminate destruction, their stubbornness to survive, or perhaps its bereft of reason, no one knows why The Outsider has an affinity for these vermin. Once per long rest you can use your Outsider's Mark to cast Conjure Animals summoning a rat swarm. Treat the rat swarm as if it was challenge rating 1 for purposes of working the spell. Once per casting you can command the swarm to devour a corpse, this prevents spells that interact with the corpse from functioning. The process of devouring the corpse takes a full minute leaving behind a gruesome scene.

Possession

Starting at 10th level, your powers of the void make you a human pupeteer. This ghostly ability allows those with The Outsiders mark to not only dominate the mind of beasts and humanoids but to possess them for a short time controlling them like a marionette. Once per long rest you can you can us your Outsider's Mark to cast dominate beast or person and may choose choose to dematerialize into the body of your target. During this time, you are unable to be targeted by spells and attacks and cannot take any other action other than controlling the dominated target or ending the effect. You have rudimentary control over the target able only to move at a walking pace and interact with objects. Though you maybe be able to move about unnoticed, you are unable to talk anyone attempting to interact with you assumes you are ill, not immediately aware the target is under the effects of magic. If you force the target to take damage, you take the same amount regardless of your resistances and must make a concentration check to continue the spell. If you fail or the target succeeds on their save throw you are ejected and fall prone. Whether you choose to end the effect, which is a free action, or if you are forcefully ejected, you exit the body to a space you choose within 5 feet of the target and they are poisoned until the end of their next turn.

Slow Time

Starting at 14th level, you are granted the most potent of The Outsider's gifts, control over the flow of time. Once per day you can use your Outsider's Mark to expend your bonus action to immediately gain an additional turn ending your current turn. Additionally, you can use this ability as a reaction to instead permanently move your initiative order to the next inline. When you reach level 17 in this class you add Time Stop as an option for your Mystic Arcanum class ability.

New Invocations

Improved Blink

Prerequisite: 7th level

The distance you blink is increased by 5 feet and no longer costs movement. *alternate blink: your blink ability also gains an additional change.

Otherworldly Athleticism

Your walking speed increases by 5 feet, and you gain a climbing and a swimming speed equal to you walking speed.

Dust to Dust

Prerequisite: 7th level

Humanoids and beasts killed by you turn to ashes leaving only their possessions behind. Aside from removing the body from being detected this prevents spells that interact with corpse such as raise dead, speak with dead, or raise zombie.

Designer Notes

Alternate Blink

You gain 3 charges you can expend a charge and use your action or bonus action to blink, moving forward rapidly to a space within 15 feet that is in line-of-sight (you can not blink through solid objects). If you don’t blink for a full round you regain 1 charge at the start of your following turn, for each subsequent round that you don’t blink you gain an additional charge until you are at max charges. This alternate blink movement follows all rules from above ability for the exception that movement does not count against your maximum movement for that turn and you could use this as both your action and bonus action to blink provided you have enough charges.

No Bone charms?

Yup, bone charms are items you obtain and are more akin to magic items than they are class features. DM’s can always, and maybe should always, implement some item tailored especially for all character at the table. For lore you can also craft your magic items from marine animal’s bones. Aside from whales, maybe Aboliths or a Kraken bones work too; this can give your character’s story direction by becoming a harpoon wielding sailor/whaler harvesting bones as willed by The Outsider.

Class features

*It is assumed that the player will pick the spells conjure animals, dominate beast, and dominate person for the class features at level 6th and 11th to function. This could be a design flaw, however, I was of the opinion it would be overpowered to give them an addition free casting of these spells. I felt that the bonus invocation reflected The Outsiders powers present in the game. The increase in invocations felt a better solution than adding new abilities or reusing spells.