Fans generally love this episode for its "Jerza" (Jellal x Erza) development and for raising the emotional stakes of the Nirvana battle.
It introduces the Nine Demon Gates of Tartaros, who use "Curses" instead of Magic, making them feel like a unique and overwhelming threat. Fairy Tail (2014) Episode 59
This episode focuses on Jellal’s amnesia and his tragic reunion with Erza. Fans generally love this episode for its "Jerza"
The arrival of Jackal and his explosive power sets a violent precedent for the rest of the season. The arrival of Jackal and his explosive power
Most viewers asking for are referring to the start of the Tartaros Arc (technically Episode 234 overall).
There are two ways to interpret "Episode 59" because the 2014 series (Season 2) often restarted its numbering or continued from the original show's count.
Alternative: Episode 59 of the Original Series ("Recollections of Jellal")