Glowing Rods are a unique key item in Remnant: From the Ashes, but if you've reached the Rhom plane, you've already gotten used to finding all sorts of odd and mysterious items in this game. Here, you'll learn what to do with Glowing Rods, and what their locations are.
Firstly, though, you use the Glowing Rods to unlock the special Akari gear set that you cannot get anywhere else. The Glowing Rods are essentially keys to the vault that has a chance to drop the armor - just so you know what you're getting into.
Remnant: From The Ashes Glowing Rod Locations
There are three Glowing Rods total, but the trick to finding them is that there's no trick. They appear as random dungeon drops, virtually anywhere in any of Rhom's several dungeons. The only real way to tackle this quest is to keep grinding dungeons until you've found all three Glowing Rods, we're afraid.
When you finally do have all three of them, you're going to want to go to the Vault of the Herald. Coincidentally, that's also one of the locations where Glowing Rods may drop (alongside Ardent Temple), but your mileage may vary. After getting there, find the unique vault entrance, and crack it open by using all three of your Glowing Rods. This will - if you're lucky - drop the Akari armor for you.
Since the Akari gear buffs your melee damage and general close-quarters capabilities, we suggest you get this set before embarking on your Corsus adventure. Best of luck, and good hunting.