Posting this here because this information is absent from the wiki, as skipping G2 was never possible in the NA server.
For players who skipped G2 through the weird cat, Paladin can be learned by talking to the weird cat again and asking to become a Paladin. The Weird Cat will then give you the paladin armor for the Ciar Dungeon White Wolf RP quest. After completing the quest the Weird Cat will tell you about Paladin skills and will teach you Spirit of Order, Power of Order, Eye of Order, and Sword of Order. The remaining skills are learned through a separate questline.
Normally for players who did G2, pages 1 and 2 were automatically in the book. Players who skipped G2 must find these pages.
Page 1:
Asking Eavan about the book of Paladin will give you a quest to deliver 5 skeleton wolf fomor scrolls. Skeleton wolves can be found in Rabbie Normal or Advanced Dungeon, Rundal Normal, or on the path to Bangor in Gairech. Completing the quest will give you the first page for the book of Paladin.
Page 2:
Asking Craig about the book of Paladin will give you a quest to get a magic powder of preservation. Craig will give you a damaged page and a pass to Barri Dungeon as well. The Dungeon consists of 2 floors with mostly normal Barri spawns (no imp spawns, vampire bats seem to be a little more common than normal). The boss is 2 werewolves and 3 gray gremlins. The reward chest will give a magic powder of preservation, this is used to complete the quest. Completing the quest will give you 100 exp and a physical 2x2 quest scroll containing the next quest.
For the 2nd quest you just need to talk to Craig, he will then tell you that a magic user needs to repair the page and he sends you to stewart. After talking to stewart you can complete the quest and get the second page for the book of Paladin.
You may refer to the Mabinogi World Wiki for the remainder of the quest as it is the same.
https://wiki.mabinogiworld.com/view/Paladin_Passive_Defense_Quest