- Fanfic Fuel:
- On top of fans tying the series back to G1 now more than ever, we have Scorpan, another G1 based character and Tirek's brother who befriended ponykind but left soon after Tirek was imprisoned. This is itself a reference to the original Scorpan, who also pulled a HeelFace Turn against Tirek near the end of the G1 pilot. Oh yes, and Discord and Tirek know each other somehow.
- Celestia says directly Tirek is unaware there's a fourth alicorn in Equestria, that being Twilight. However, Cadance's backstory as a mortal pegasus who became an alicorn is established in tie-in novels, implying there was another "third" alicorn besides Celestia and Luna when Tirek was sealed.
- Hilarious in Hindsight: The general consensus in the fandom was largely against the belief that Centaurs would exist in the world of MLP:FiM because it was thought to require actual humans to exist as well. Tirek's introduction ended that argument in favor of the pro-Centaur fans.
- Most Wonderful Sound: Celestia, Luna and Cadance singing three-part harmony in "You'll Play Your Part".
- They Wasted a Perfectly Good Character: Scorpan is mentioned during Tirek's backstory as Tirek's brother, and is never seen or mentioned again, other than in the next episode when Tirek says that the medallion he gave to Discord belonged to Scorpan. Whether it means that Tirek killed Scorpan in revenge, or that he was merely unavailable as he lives in a foreign country and the only reliable long distance communication is via Spike and Celestia, leaves his fate ambiguous.
- Unexpected Character:
- Tirek. Considering Hasbro lost the rights to a lot of their G1 properties, a revamp of the original G1 villain (or at least a character based off him) certainly counts.
- Scorpan, here re-imagined as Tirek's brother, also counts, due to having less a role in the original story than Tirek, but here being the one responsible for his original defeat.
YMMV / My Little Pony: Friendship Is Magic S4 E25 "Twilight's Kingdom – Part 1"