Just a quick tip for today. In several threads across the past week I've seen people talk about things like villain monologues. I've also had several people I play with comment on them. GMs have wondered how to do them well - I blame Matt Mercer for this. Players have talked about how they've reacted to them.
The thing is, in 20+ years of gaming I have literally only seen two tables allow a villain to monologue. One was Critical Role, where the players are all very good at letting everyone have their moment and have a blast just watching their friends go ham on their acting chops to deliver a moment. The other was in a superhero game I ran - and I paid the players to make it happen.
That's right, I gave everyone a hero point and told them "the villain is going to monologue, you can't interrupt it. The hero point can be used right after to help you acquire whatever benefit you want to get out of the break while they monologue."
I feel the Hero Point was well done. I paid the players, said what would happen - paid for GM fiat effectively - and the hero points also let the PCs get something out of the monologue so their characters didn't just have to sit there. I also liked this because it felt like a comic book. The villain monologues while the hero catches their breath, bandages a wound, looks around, and plans. The monologue stops and the fight picks up again but now the hero has some momentum back in their favor.
Outside of that? Players will always interrupt. Generally no one wants to sit there and here a speech about how powerful or inevitable something is. That's free time to get some hits in. The most surprising thing to me about how reliable the player interruption is, is how many people - players and GMs - almost seem surprised to find out that it is a common reaction.
So if you need a monologue how do you do it? Three options:
1) Keep it short. No more than 3 to 5 sentences tops. Something you can deliver in one turn on initiative without going overboard on what you allow for speaking.
2) Pay the players in some way - like with a Hero Point
3) Arrange the situation so the players actually can't interrupt the monologue, such as it being delivered on a television - and just give them the handout for what is being said.
Actually, I lied. There are a couple others.
4) Spread the monologue up over multiple rounds in the combat, or just grandstand in one round for it, but even then there will be interruptions as players hit the talking villain.
5) Ask your players to let you have this one moment, at which point they may give you one so enjoy it.
But what's really fun? See if you can arrange for a player character to want to give a monologue...then interrupt them. Turn about is fair play after all.