Attunement Slots | Dark Souls Wiki
This stat is most important for deciding how many Attunement Slots you'll have, which in turn allows players to equip and use more types of magic at once.
Attunement | Dark Souls 3 Wiki
It can have been more akin to DS2 or even DS3's variation of Attunement albeit slightly toned down to fit original Dark Souls 1 design (considering in DS2 Attunement also increased casting speed).
Stats - DarkSouls II Wiki - darksouls2.wikidot.com
The Southern Ritual Band is a ring in Dark Souls II. The Southern Ritual Band increases the amount of attunement slots a player can have.