@Dreaming what even constitutes a race as being useful in the War against Unbeing? Considering the god-like attributes involved in the primary actors, I'm left wondering if all the Lek-kego could ever accomplish would be stalling Unbeing by distracting part of it. In which case ... well mission accomplished?
Neither your people nor theirs are often capable of harming the other so you must turn to other methods. The frontline of the War is at the forefront of the tide of Unbeing, where, outside of defined little pockets such as your prison, the nature of reality is far more
wobbly due to the constant loss and erosion of fundamental attributes. Out past that point, where the tide has been and gone, is nothing. The tide itself is the boundary of the cosmos, of not just the universe but also of what is possible to perceive or even
imagine about it. It is the weapon of the Unbeing and though it may even unmake things like you with sufficient exposure, that's not really the point of it. The Unbeing isn't really trying to kill your people, that's just secondary to their objective of unmaking reality beneath you. Accomplish the latter and the former will follow.
But even though neither of you are capable of harming the other in all but the most strenuous circumstances, the things of the Unbeing are poisoned by the stuff of Creation. The more Unbeing is forced to interact with things and peoples of reality, the more it must admit that reality is real (or else it wouldn't be interacting with it). It gets into them like a poison and makes them more real even as they do the reverse to reality, tying them to reality in a web of context that can ultimately entomb them in Creation like an insect in amber. All Unbeing that you'd ever come into contact with is already at least a little tainted by this, due to the virtue that they're fighting a war at all, but it varies from one to another and the more they must do battle against things that aren't your people, numinous beings who are almost as removed from reality as they are, but creatures and things made in the universe, the more it traps them. Even trying to jump back into time or wipe them from existence requires admitting that physics and dimensions exist. Hence you get things like your current cell-mate, whose previous meddling with your experiment wound up with them wedged into the walls of your prison.
To that end, your people cultivate universes and civilisations to be warriors, though in this case 'warrior' can apply just as easily to denizens who sing at the Unbeing as much as they do denizens who blast at them with star-fleets or impale them with demigod blades. They don't even have to survive or be involved themselves: their entire existence and history can be just to peak in the creation of a single weapon or idea that justifies themselves. Out in the frontlines, where reality is extremely tenuous, the battlefield is often a single singularity of space or time where ones relative dimensions or the cosmic impossibilities of things interacting with something bigger than a universe stops mattering.
Besides, 'bigger than a universe' is not only extremely relative (
you are bigger than your current universe but it is scant more than a light-year and a few hundred millennia across) but mostly meaningless as a bragging point when space and form are illusion.
