The incredible technology of the Maxohlx and the Rindhalu did not extend to creating, or even operating, the wormholes that made long-range interstellar flight practical. Those wormholes were created millions of years ago, by a long-gone species that is unknown, other than what they left behind. The Kristang called the wormhole-builders the Elders. Wormholes didn't care who went through them, and there was no known way to control one, or shut it off. Or damage it, even a nuke had no effect. The wormholes worked, and that's all we needed to know.

Then we got to The Rules.

The Rules were the Rules Of Engagement for combat. They applied to both sides, and were strictly enforced by the Maxohlx and the Rindhalu. The Rules explained why the war had been going on for many thousands of years, why both sides hadn't wiped each other out a long time ago. The basis of The Rules was that the Maxohlx and the Rindhalu couldn't afford to seriously fight each other directly, in the same way that America and China couldn't fight each other. On Earth, countries with megatons of nukes couldn't fight without destroying their own countries. Out in the galaxy, species with weapons that made nukes look like firecrackers also could not afford to fight each other directly. So they fought through their client species, and those species also had clients, and so on. Most of the actual fighting and dying was done by third-tier species like the Ruhar and the Kristang. And by their clients. Like humans.

Anyway, here are The Rules.

You'd better grab a pencil and paper.

Rule Number One; no use of nukes, or other types of radiological weapons, on or near an inhabited planet, or even potentially habitable planet. No antimatter either, because such a weapon produces hard radiation even if it is short-lived. This rule was listed first, because the Maxolhx and the Rindhalu didn't want their grubby underlings contaminating a planet they may later want for themselves. Even in the vastness of the Milky Way, the number of habitable planets within practical range of a wormhole was limited, so both sides didn't want useful planets removed from productive use because some jackass went crazy with nukes.

Rule Number Two was no chemical weapons, for the same reason as Rule Number One. Nasty chemicals could linger in the environment for a long, long time. They didn't quite say that any species abandoning a planet was supposed to sweep up after themselves and take their trash with them, I figured that was implied.

Rule Number Three, no use of nano weapons. Nanotech was widely used to make things, but it could not be used as a weapon. Even the Kristang weren't sure of the basis for this rule, but ancient rumor held there was an incident where nanotech go loose, and caused that entire star system to be quarantined, permanently. Hence, nano weapons were a huge November Golf in the war.