- Harlequin Crest, colloquially known as "Shaco" in Diablo II, was left at Ogden's Tavern of the Rising Sun by a mage that passed by.
- The "magic rock" spoken of in the aptly named quest, "The Magic Rock," is likely to be the Sightless Eye.
- Wirt's mother, Canace, died of a broken heart when he was kidnapped by the demons that took his leg.
- Ogden has a wife named Garda.
- Farnham drinks because of the horrors he experienced within the Cathedral.
- Skeletons, Zombies, Overlords, and Magma Demons are minions of Mephisto.
- Fallen Ones, Goat Men, Spitting Terrors, and Horned Demons are minions of Baal.
- Winged Fiends, Scavengers, The Hidden, and Gargoyles are minions of Diablo.
- Fara, the blacksmith from Lut Gholein, is a paladin.
- Elzix, the innkeeper of the Desert Rain Inn in Lut Gholein, is most likely a retired member of the Thieves Guild.
- Charsi, the blacksmith from the Rogue Encampment, was born a barbarian, but raised under The Sisterhood of the Sightless Eye
- Blood Raven is the rogue from Diablo I.
- The Summoner is the sorcerer from Diablo I.
- Andariel does not like fire.
- The only Zakarumite who stood against Mephisto's corruption of the Zakarum Church in Travincal was Khalim, the Que-Hegan at the time.
- Natalya was sent to Kurast to keep an eye on Ormus, whose mysteries have yet to be explored.
- It is likely that Lyndon the Scoundrel once had a fling with Gillian the Barmaid, likely after she fled to Caldeum with Adria.
- The Sorceress from Diablo II is named Isendra and mentored Li-Ming, the Wizard from Diablo III.
- The Necromancer from Diablo II mentored Mehtan the Necromancer, found in Act II of Diablo III.
- Adria led the Coven with Mahgda before she left for Tristram 20 years prior to Diablo III.
- Kormac serves the Zakarum Church which does not seem to have risen from its corruption as it is brainwashing its warriors now as explained by Kormac.
- Town portals work by linking the caster to a nearby ancient Horadric gateway.
- Demons don't have a use for gold, but hoard it anyway.
- If more than one ring was worn on a hand, their powers would interfere, nullifying both.
- Izual was corrupted after leading an attack against the Hellforge and his runeblade, Azurewrath, has been lost ever since.