Not only do the many sub-quests in Tales of Arise serve as a nice change of pace from the game's main story, but they're also a great way of earning Gald and SP, which can be used to purchase new armor for Alphen and the rest of the party and unlock new skills respectively. There are 70 of these sub-quests in total, 12 of which can be found in the game's second realm, Cyslodia.
The majority of Cyslodia's sub-quests can be completed before it's time to leave for Menancia, though there are a handful that can only be tackled once players are approaching the very end of Tales of Arise's epic story. It's also worth noting that several of them involve taking down monstrous Gigant Zeugles, so players will need to make sure that their party is at an appropriate level before taking them on.
Travel to Nevira Snowplains and defeat the three groups of Zeugles.
Rewards
Life Bottle (x2)
1,800 Gald
175 SP
Survey Says…
Quest Giver
Bregon (Bregon's Hideout)
Unlock Requirements
Complete the "Culling the Snowplain Herd" sub-quest.
Strategy
Speak to the three marked NPCs who are scattered throughout Cysloden and then return to Bregon. The party will then need to defeat the Polycephus Gigant Zeugle (level 21) in the basement of Riville Prison Tower.
Rewards
2,700 Gald
310 SP
Opening up Trade
Quest Giver
Bregon (Bregon's Hideout)
Unlock Requirements
Complete the "Survey Says…" sub-quest.
Strategy
Head to the Ulvhan Grotto area and defeat the Boisterous Roper Gigan Zeugle (level 15).
Rewards
2,200 Gald
250 SP
In Sync
Quest Giver
Patvo (Cysloden)
Unlock Requirements
Defeat Vholran at Del Fharis Castle and then return to Cyslodia via the Forland Mountains.
Strategy
Head to the Frozen Valley area and defeat the Agony Keeper Gigant Zeugle (level 39)