The Raven Queen warlock patron (from Unearthed Arcana: Warlock & Wizard) grants the Sentinel Raven feature at 1st level, part of which says:
While perched on your shoulder, the raven can’t be targeted by any attack or other harmful effect; only you can cast spells on it; it can’t take damage; and it is incapacitated.
[…]
In combat, you roll initiative for the raven and control how it acts. If it is slain by a creature, you gain advantage on all attack rolls against the killer for the next 24 hours.
Can you have the Sentinel Raven start out perched on your shoulder and then, on its turn, have it lift off your shoulder, use the Help action to give you advantage on an attack, and then perch on your shoulder again? This would make it unable to be targeted or damaged, but still give you (the warlock) advantage on your next attack.
Am I correctly interpreting the rules here? Is it possible to have the Sentinel Raven start perched so it can't be harmed, Help on its turn, and perch again at the end of its turn?
Best Answer
Yes...
At the time of this answer, the Raven Queen patron is an Unearthed Arcana option and so it is subject to change if and when it is ever released in an official addition.
Given this preface, yes, you can use the raven as you describe. However, the raven has its own initiative which means the advantage granted by its Help action could be used up by another player before the Warlock's turn. If this is not the case (or the DM has it act at the same time as your character), you are free to use the advantage for yourself.
Do note that the raven does not possess the Flyby trait that an owl has, which means you have to be careful to only use its Help action against a target that has already used its reaction (unless you are within the enemy's reach). Otherwise, you risk losing the raven to an attack of opportunity when it flies back to perch on your shoulder. (Hat tip V2Blast)
Also, note that while the raven spirit functions like a familiar (which can use its action to Help the controlling character & player), critically, it is not a familiar (at no point is it called a familiar and it is not summoned using the Find Familiar spell). This means that if, at level 3, you also take the Pact of the Chain, you could have 2 creatures that fly around and Help you/other players.