HIGHLY HIGHLY HIGHLY Situational with multiple players working and using numerous resources to set up this one spell (and risking a teleport failure).
You are proving my point - it is very situational.
I want an example that does not rely on other PCs having the exact spells you need to make it work and that you don't have to scout ahead of time or cast a spell ahead of time or have a specific corner case build just for this one fight.
Claiming something is good on a multiclass build using a 2014 Subclass and a Warlock dip while also needing other specific spells to make it work is situational.
If this is such a powerful spell and not situtional, it should be usable on a straight class spell caster ina situation that does not require precasting or a ton of extra setup.
For example - I cast Forcecage on him and just use Cantrips until he is dead. That is an extremely powerful spell and will work most of the time. It will work on most of the monsters I named, and it will work regardless of what kind of caster the PC is, regardless of his allies and it will even usually work with no allies at all. There are some enemies it does not work against but it is widely useable and relatively robust across a large range of party makeups with a large range of spell caster builds, with little specificity on initiative, or pre-scounting an area, or precasting a spell and it works against a large number of powerful monsters ... i.e. it is not situational
Because you need to get within 15 feet to get any CME damage.
Yes they can. Where are you getting this from? Please provide a reference that states they can not use legendaries before their turn. Monster Manual on page 11 clearly says they use Legendary actions "at the end of another creatures turn"
You don't understand the rules.
Vecna: Vecna can use Fell Rebuke as a REACTION and teleport away from you and out of range after you hit him with the first attack (while also damaging you) and he gets 3 reactions a round. 12d8 plus whatever that attack is will not kill him, not even if you precast it, win initiative and crit. This will NEVER work against Vecna unless he is incapacitated before you try to pull this off and well if that is the case, what beat him being incapactitated, not your spell.
Demogorgon: Demogorgon has numerous things he can use. He can stun you from 120feet away with a Legendary action (which he absolutley can use before he goes in initiative). He also has spells that can completely debilitate you including Fear and Feeblemind and he can cast those on a legendary action too and that is if he does not win initiative. Now depending on your class you have a chance of beating that save which is why I said with some luck or in certain situations it will work against him. Not most of the time though.
Zariel: Zariel can use a Legendary action to teleport (and she can do it before the caster's turn) and will not be anywhere near a the caster using CME.
Kraken: A Kraken has a tentacle attack and fling both of which can be done with legendary actions. As I said it is situationally useful with a Kraken. Most of the time it is not going to work. With some lucky rolls and positioning that favors the caster it can work. It is situationally effective.
Yenoghu: Yenoghu can move 50 feet as a legendary action and he can also use his flail which can paralyze the caster as a legendary action and cause a concentration save even if he is not paralyzed. RAW he can do these before he goes in combat. Playing it smart with the 50 foot move he will usually be able to avoid being within 15 feet of you, playing it bloodthirsty and attacking the caster with legendary actions will make it likely to cause a drop in concentration. Either way this can be situationally effective.
Reactions work whenever the triggering event occurs. You can use it on your turn, the enemies turn, between turns, whenever the trigger happens. In the new rules you can even use a reaction before your turn if you are surprised. Vecna is the only monster I listed with reactions in the stat block. The others have Legendary actions (in the old statblock). Legendary actions that work on the end of OTHER CREATURE'S TURNS.
Please read the rules if you want to continue this discussion. You do not understand how Legendary Actions work and it is of no value discussing how things work if you fundamentally do not understand the rules.
If you keep insisting that Legendary actions come at the end of the Legendary creature's turn, please provide a page number where any official rulebook states this. Twice now, I've provided the page that says it can be used at other times.
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