Strengths - he's an archangel. Unfortunately, that means that he's incredibly powerful. I'm not talking just physically either. He can bend time, create alternate universes, get inside your head...if you can think of it, Lucifer can do it. So can the other angels.
Weaknesses - we don't know of many. There's an angel sword, but they're scattered few and far between and I doubt any of the angels are gonna be loaning theirs out to us any time soon. There are symbols that you can use to ward your home from him, along with symbols that you can use to send him or any other angel away if you can get it working fast enough. [Insert handy dandy file with images and instructions on the uses of each one here.]I don't know if I can trust you with the ring plan yet, so
Tactics - he hasn't been too open about his playbook, but we do know he's been scattering his demons all over the place to spy on us. I'm sure he's got even more planted around the world working to set up whatever big end of the world schemes he's got hidden up his sleeve. Then there's the Horsemen. We've dealt with most of them, but...well. You know what they do.
Allies and numbers - all of Hell. Most of Heaven. He's got us outnumbered in every way. I haven't seen him working with anyone from any other worlds lately, so that's not too big of a concern.
OTHER SUPERNATURAL CREATURES
Other creatures - there are way too many for me to list. If you've heard of it, it probably exists here. Vampires included.
Demons - their weaknesses are: holy water, devil's traps [image], and exorcisms. They've got a number of abilities, depending on the type of demon and how powerful it is, but the basics come down to telekinesis, strength, and the ability to possess a person.
Magic - we've got your standard witches, if that's what you mean. I guess beyond that, you'd have to look at the seal. Plenty of magic fell through and I'm assuming plenty of magic is what's keeping that thing going. So lots would be the answer you're probably looking for.
That's more of an outline than anything. There are a lot more details following up on all that, but you'd be better off learning in a hands on situation than hearing it all from me.
If you're a vampire, you're going to need to eat. What are you eating? Where are you getting your food? Beyond surviving, what are your plans here? Are you going to be a problem?