"That sounds promising. As much as can be expected, anyway." Blastralion folds his hands in front of himself and his carven face adopts a thoughtful expression. "To explain, I suppose I must first describe my own capabilities. I and many of my allies possess a form of magic which lets us travel between universes. To visit a particular universe, we must identify a target universe and 'anchor' to it. As a general rule, anchoring converts any accompanying magic to match the...physical rules...of the destination universe. If no such conversion is possible, such as when anchoring to a world which contains no magic at all, then non-travel forms of magic cease to function while anchored there. Usefully, and sometimes annoyingly, our method of travel also tweaks skills and experiences to be relevant to the destination universe. As an example, some universes I have visited possess advanced nonmagical weaponry. Traveling to such a world would convert my skill in swordsmanship to a skill with those advanced weapons. Since I am currently anchored to a world with less advanced mundane craftsmanship, I know that advanced weapons exist but not how to make or use them."
"Whatever world I'm in, I retain a few core skills and abilities. Among these are the ability to anchor-and-travel elsewhere, the durable and versatile crystalline form I wear, and the accumulated combat experience of centuries spent fighting various threats. I come from a species that takes great joy in combat, and I am no exception. The majority of us choose to leverage our combination of power, prowess, and patience for grueling training to helpful ends, typically by locating worlds in danger of hostile invasion and thoroughly crushing said invasion." There's that savage smile again, perhaps tinged with a touch of wistfulness.
"It may sound difficult for a roving band of warriors to find easily-justifiable targets. But it turns out, the cluster of universes reachable by anchor-and-travel magic include a lot of variety. And somewhere in the multiverse, there's usually some form of demonic invasion or hideously oppressive regime to be fought.
"My allies and I recently encountered a collection of species we dub 'Netherlings', which range in power from 'small biting insect' to 'eldritch star-eating monstrosity.' The few things they seem to have in common are a shared origin universe and a desire to violently expand into others, killing, torturing, enslaving, or eating the inhabitants as suits their fancy. They have a form of anchor-and-travel magic of their own, a portal-based one, but it is enormously energy-intensive to open a portal. The more powerful the entity who wishes to travel, the more energy it takes to send them, and any given entity usually cannot muster anywhere near the power required to move themselves across universes. So their invasions tend to be numerous weaker Netherlings sponsored by one or more powerful Netherlings who hope their minions can establish a foothold on their behalf - by butchering the locals, of course.
"Naturally, we are at war.
"My alliance includes beings who can deal with star-eating monstrosities, but their time is valuable in proportion to their strength. It is important for us to resolve any given incursion with the absolute minimum expenditure of resources, for the Netherlings outnumber us on a vast scale. We have largely succeeded in thwarting their expansions thus far, through a combination of better coordination, elite training, brilliant strategic leadership, tragic sacrifice, and sheer blatant cheating with exploitable magic and advanced weaponry.
"My current assignment in this multiversal war has placed me in an odd and awkward position. My usual approach is to anchor-and-travel to an imperiled world, learn how to best use their local magical and martial advantages, and cajole or coerce their leaders into cooperating to destroy the Netherlings' portal.
"Unfortunately, the universe where I'm currently anchored seems to be lacking in exploitable magic. I'm having to fight off armies of monsters with little more than archers and men-at-arms for support. I was beginning to fear that I would have to either call in reinforcements from elsewhere or abandon this world entirely - and then I opened a door to an interdimensional bar." He gestures expansively to encompass the current locale. "Milliways seems to operate on different rules than anchoring does. If your magic carries over into my anchored world, then any help you can offer would go a long way. I can guarantee you the time to work, if needed. We can do quite a bit with magic of the 'erase an auditorium' variety, and we may even be able to close the Netherling portal. That would set them back tremendously, and it's likely that whomever sponsored this little invasion would give it up as a bad job. I could handle cleanup from there.
"For quota-meeting purposes, the Netherlings tend to outnumber their victims significantly, and many of them are demonstrably people. Unsalvageably evil people, mind, but people nonetheless."