Knights of Cygnus DPS

Does that mean that your adventurer doesn't get any buff even if your have a lvl 120 Cygnus, but the Cybus gets a buff from your adventurer?.

Your adventurers get buffs even if you don't have a cygnus (eg. level 50 and 30 adventurers will get level 3 and 5 Blessing). If you have a 120 Cygnus, your adventurers would get 12 Blessing, unless your account has multiple 130+ adventurers (in which case they'd each get 13+ blessing, and so would the Cygnus)