Thanks to the data you generated, the Hidden have found that resonant runes are essentially a Hive-magic imitation of the Relic. Which means the compatible resonance of the Osmic Fragments are actually an indication of a Weapon Pattern stored.

Or rather, a piece of one. Hence, Immaru's determination to collect all the fragments.

Then, as soon as he'd make the pattern whole, he could use the runes to shape as many specialized weapons the Lucent Brood could ever ask for.

If only you hadn't gotten your hands on the fragments first. Without those, Immaru will have to improvise.

And he undoubtedly will. So, Ikora proposes a turning of the tables. According to the Hidden, the shaping ritual is meant to take place in Queen's Bailey.

Take the Osmic Fragment and use it to lure in Immaru. If you play this right, you can grab your culprit and his remaining supplies in one fell swoop.