Can a spell caster attack and/or cast spells while using a familiar's senses?

Question

Similar to:

• Perception checks through a familiar's eyes
• Can I act normally while seeing through my familiar's eyes?

While looking through a familiar's senses, the owner goes blind and deaf. Instead they see and hear what the familiar sees and hears. In some cases, this is even better than the spell caster (blind sense, Devil's Sight, etc).

If the familiar is perched on your shoulder (or pocket, head, or somewhere else on your person), can the owner function normally in all respects, including attacking and casting spells?

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As an example, a Tiefling at level 5 I can cast Darkness. Per the spell:

A creature with darkvision can't see through this darkness, and nonmagical light can't illuminate it.

But my imp familiar (Pact of the Chain) has Devil's Sight:

Magical darkness doesn't impede the imp's darkvision.

So if the Tiefling gives over their senses to the imp, they would be able to see normally (or at least to the level of darkvision). Can the warlock now attack the creatures caught in the Darkness spell via sword and/or via spell?

Please do not get hung up on the example

I'm not asking for the best way to see in magical Darkness. The example is just that, an example of using a familiar senses instead of your own in "real time".

For a non-magical example; assume the familiar owner is naturally blind (defect from birth), can they use the familiar's senses to navigate the world, cast spells, and attack evil?

Answer 1

Yes, but don't forget about the fact that it requires an action.

To see through your familiar's senses, it requires your action, as do most spells and attacks. If, for example, you had Misty Step (bonus action, can teleport to a location you can see within 30 feet of you), you should be able to teleport to a location your familiar can see as long as its within the appropriate ranges (compounded by the question Can a wizard use his familiar's senses to enlarge his "you can see" area?). Considering the effect has no mention on your speed, mobility, bonus actions or reactions, then the simplest conclusion is that they are not impacted at all, so long as you obey any of the new changes to your perspective.

This isn't precisely written territory, however, so your DM may have an alternative viewpoint.

For example, I actually just asked this to my DM, whether I could use Mage Hand Legerdemain while seeing through a familiar. His response was that, while it normally shouldn't be possible for normal people, due to the Mage Hand being invisible and not having access to my own senses, my naturally high intelligence is enough to do it without requiring additional difficulty checks. That being said, Your Mileage May Vary.

Answer 2

Yes, you can attack while using its senses, but...

Solving the vision problem with this method introduces several limitations. Seeing through your familiar's eyes uses your action each round that you do so, which severely limits which spells you can cast, and may eliminate your ability to make any weapon attacks. Multiclassing with fighter or sorcerer may be required to achieve what you want. Your spells also still need a clear path from you (not your familiar) to your target.