A Warlock with the Raven Queen patron can use the 6th level Soul of the Raven pact ability to merge with the Sentinel Raven, as written:
As a Bonus action when your raven is perched on your shoulder, your body merges with your raven’s form. While merged, you become Tiny, you replace your speed with the raven’s, and you can use your action only to Dash, Disengage, Dodge, Help, Hide, or Search. During this time, you gain the benefits of your raven being perched on your shoulder.
Under the description of the Sentinel Raven, it 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.
Does this mean the Warlock cannot be targeted by attacks or harmful spells while merged with the Raven? In the same vein, if she CAN be targeted, would her AC be that of the Raven or her own? What about physical statistics?