Things You'll Need
Instructions
Work your way up from the lowest levels using the old version of the game originally issued in the 1970's and known simply as Dungeons &Dragons, distinct from Advanced Dungeons &Dragons which had a slightly different set of rules. In the original boxed sets of D &D, there were 36 levels through which a player's character could pass. After reaching 36th level, game participants could buy the Immortal rules, which transitioned powerful, high level characters into the immortal realm. This will involve completing quests.
Begin your campaign with the immortal rules and you will not have to worry about working your way up there. SInce Dungeons &Dragons is controlled by a person who functons as the dungeon master and has the final say in all issues, this person could simply start the adventuring characters out as immortals. This is not unusual, since many D &D adventure modules make it possible for characters to simply assume identities of medium or high level charcaters for the duration of a campaign.
Find a "Ring of Wishes" during one of your adventures and wish for immortality. This quick route to immortality may have more drawbacks than the other methods. The wish will certainly make you immortal, but the dungeon master may turn you into an immortal green slime.
Convince a powerful spell-caster to cast a "Wish" spell or "Commune with the gods." The latter spell may require going on a quest or doing some favor for a deity. This route may not be as fast as the wish but you have a better chance to control just what you are when you become immortal.