From the patch notes: you use the Goddess equipment storage UI to upgrade your Guardian items (weapons, subweapons, armor) using Guardian Seals as materials (as you would use Vasilisa scales to upgrade Vasilisa items for example). Guardian Seals drop at a very high rate from random mobs (no level restriction), so I strongly recommend to farm them on a high density/low level mob map like Tenet Garden.
Yes. You use the same UI as you would to upgrade Dysnai to Vasilisa or Vasilisa to Falouros (Succession tab). As for the other sets, you upgrade to the next tier once your item is enhanced to +20 with Seals (and it should become +10 – need to test that).
Transcendance system is obsolete. The last items that require transcendance to be upgraded are the Luciferie accessories for alts to be turned into Isidavie (for you main you now get a full +15 Isidavie set from episode 14-1 rewards). For higher items (post 470), transcendance is included in the upgrading system, as it requires blessed shards and yields much better stats.
Not at all. The new system is tailored for level 1 characters and your Guardian equipment will follow you up to level 480 now, and you will be able to turn the Royal stuff into Reservoir/Falouros by simply succeeding +20 Royal Guardian set. From what I’ve seen, they only boosted episode 1-13 field mobs so they aren’t oneshotted by basic attacks anymore, but they’re still easy to kill with your skills (bosses didn’t get touched they’re even weaker than field mobs now – this is stupid).
For characters that are not level 1 and want to use this system: you get the Guardian stuff from Wings of Vaivora NPC. The Growth and Kedorian items are gone, you can only get Guardian boxes now. A slight overlook from the devs is that you need to get four boxes since they contain a full set of armor but only one weapon/subweapon and you can equip four of these as any other Goddess tier set. So get four boxes, open them to get two weapons, two subweapons, one set of armor and you can discard the three duplicate armor sets that will come out of the extra boxes.
Just upgrade each item one by one as you get Seals until +20, then suceed them when you reach the level thresholds of 280 and 480.