Solorius Event Staff NPCs in each capital city give out all the relevant Solorius quests:

 Sock Quest

The initial sock quests send the player out to look for Solorius socks that have been stolen by holiday-ruining pranksters. Once these quests have been completed, another sock quest becomes available, and this one can be repeated up to ten times.

 Rewards

Solorius Cap – decorative hat item

Gift Bundle – contains one each of the three festival feast items “[Event] Solorius Torte”, “[Event] Solorius Bread”, and “[Event] Solorius Punch”, which each buff three different stats.

Hat Box – contains one of the following four decorative hat items: “[Event] Solorius Deer Hat; “[Event] Solorius Tam”; “[Event] Solorius Cloche Hat”; “[Event] Solorius Tuque”.

The Festival Staff NPCs also give Find the Shugo type quests, in which the player must track down a staffer who has volunteered to help with the festivities, but has disappeared before accepting any reward. These quests are repeatable up to five times.

1. The Elyos quest, “[Event] Solorius Joy”, has the player track down Squeegenerk in Verteron. He asks you to give his reward away to Jenel, on the Cantas Coast, and to Neltonia, in Tolbas Village.
 

2. The Asmodian quest, “[Event] Festive Us”, has the player track down Zubinerk in Altgard. He asks you to give his reward to Skanin, at Basfelt Village, and to Grak, at the Heart of Impetusium.

 Winter Bear Candy transforms the player into a Winter bear that can use skills for 60 minutes. It buffs Max HP, Max MP, Attack Speed, and Casting Speed.

The “Token of Gratitude” is a gift box item containing two dyes of one of the following colors: Teal, Blue, Brown, Purple.