There are no specific rules for detecting illusions besides what is in the spell description:
A creature that uses its action to examine the image can determine that it is an Illusion with a successful Intelligence (Investigation) check against your spell save DC. If a creature discerns the Illusion for what it is, the creature can see through the image, ...
Not according to the rules
The rules say this about torches:
Torch. A torch burns for 1 hour, providing bright light in a 20-‐‑foot radius and dim light for an additional 20 feet. If you make a melee attack with a burning torch and hit, it deals 1 fire damage.
The light spells has this description:
You touch one object that is no larger than 10 feet ...
Regenerate is a Spell built explicitly for this purpose and has no costly material components. It is known by every Druid or Cleric capable of casting 7th level spells. A proper Religion or Nature check to know this in the game world and you now have reason to quest to find one.
Your character should have faith in a world where the priest of gods hand out ...
When not using vision to target the recipient of mirror image, the effects of the spell do not apply.
tl;dr Either attack at disadvantage not using sight or have blindsight
Creatures with blindsight are unaffected by mirror image
Creatures with blindsight also come with the condition immunity to being blinded. This tells us that they do not depend on ...
Keen Smell and Hearing
Keen only gives advantage on perception checks with those senses, so as written it isn't enough. If a wolf closed its eyes, it'd be attacking at disadvantage; thus we know it relies on its sight. That said, I am personally tempted to rule that with perception check vs the spell the DC if it came up at my table.
Keen Hearing and ...
The Darkness spell gives enemies disadvantage when attacking me
Yes, however, unless you can see in the dark (e.g. Warlock's Devil's Sight Invocation) then you are Blinded which gives enemies advantage to hitting you, cancelling out the disadvantage.
I can’t be targeted directly with a save spell.
Only if the particular spell requires a target "that you ...
The rule on Unseen Attackers and Targets reads:
When you attack a target that you can't see, you have disadvantage on the attack roll.
So this part of Darkness works as you believe. Note, without the Devil's Sight it would be an even roll because they would have advantage attacking a blinded creature.
However, the rule on spell targeting reads:...
I'm going to go out on a limb and say that there aren't any general rules that govern the visibility of magical effects in the Wizards of the Coast-published Dungeons & Dragons, Third Edition corpus. That is, the game's general silence on this issue is the general rule. A magical effect is only as visible as the specific magical effect's description says ...
The Ersatz Eye
The Ersatz Eye (XGtE, page 137) grants vision when placed in the socket of a missing eye - the perfect Father's Day gift for a Vecna cultist or a Treasure Island pirate.
If vision in only one eye is still too much, perhaps your DM would agree to further nerf it in one of the following ways:
It's defective, and vision past 15 feet is just ...
Manual of the Planes, p.55 says, in part:
Unlike most planes, the Ethereal Plane allows vision across the planar border to the plane it’s coexistent with: the Material Plane. No matter where you are on the Ethereal Plane, you can see the corresponding part of the Material Plane. Vision is limited, however, to 60 feet both on the Ethereal Plane ...
I would say that if nothing is specified about the ghost's vision explicitly, then it is just like any other monster type / playable race.
Those monster who are blind usually specify it in the monster's stat block. If they have the ability to use scent, have blindsight or darkvision (and any other such power/weakness for that matter), it is usually ...
The find familiar spell is not on the sorcerer spell list, so you would either need to take a level in wizard to cast it, or use a ring of spell storing or ioun stone of reserve to have someone else cast the spell for you. Find familiar allows you to see through your familiar's eyes:
While your familiar is within 100 feet of you, you can ...
Sacred weapon would create bright light for a 20 ft radius:
As an action, you can imbue one weapon that you are holding with positive energy, using your Channel Divinity. For 1 minute, [...] weapon also emits bright light in a 20-foot radius and dim light 20 feet beyond that.
--- Player's Handbook, p. 86
Meaning any creature within 20 ...
By RAW, the rogue can sneak attack as long as the target has an enemy within 5 ft of it
From the Rogue's Sneak attack:
You don’t need advantage on the attack roll if another enemy of the target is within 5 feet of it, that enemy isn’t incapacitated, and you don’t have disadvantage on the attack roll.
and from the Basic Rules(Emphasis Mine)