If you're looking to do so there are three further upgrades to relics. Atma requires a grind to obtain 12 unique stone from fates. the quest begins with Gerolt, the man who refurbished your relic. After you upgrade to Atma you work towards Animus which requires books to increase stats. These books have objectives to complete and they cost 1500 myth a piece. I have yet to get to Novus but that is the last tier available thus far.