Rio Sakurline War Arc

A major arc in the middle of season 2 where Rio Sakurline, Ayumi Sakurline, Mayo & Terira team up to fight against the Necropolis high students, faculty and the Phantom Blades Gang. In the events leading up the arc, many characters backstories are revealed such as Spade & Specht's. During the arc Ayumi's backstory is also revealed and she reveals to Spade and Specht about her being their half-sister. On top of that, the faculty and students of Necropolis High, although they also despise the Phantom Blades Gang as much as they despise Terira and Mayo, have no choice but to team up with the gang in the war arc. At the end of that arc, several henchmen of Terira are captured or killed, Terira and Mayo flee and go into hiding, Several phantom blades members are injured or killed, Judith Vesperia dies, Rita Mordio (series ver) & Nurse Lolita are knocked unconscious (but they both survived) and a bunch of other stuff. When Rita regains consciousness she blames herself for Judith's death and that it should have been her who should have died and not Judith. (The specific episodes that the arc lasts from happen to be S2 EP 47 to S2 EP 64.)

Other Arcs & Major events in the series.

Introduction Arc. (S1 EP 1 to S1 EP 6)

(1st intro and outro themes of the series are debuted here)

1st Terira & Mayo Attack Arc (S1 EP 9 to S1 EP 14) (New intro and outro of S1)

Shipping Club Arc (S1 EP 15 through S1 EP 17) (Shipping club through the end of Season 1 have the same intro and outro theme but with different visuals representing that arc.)

LeiaXSpecht Confession (S1 EP 18)

2nd Terira & Mayo Attack Arc (S1 EP 19 to S1 EP 20.)

(Nothing too special on S1 EP 21 & S1 EP 22.) (End of 1st season)

Sakura & Lacey Introduction Arc (S2 EP 23 to S2 EP 24). (New intro and outro theme for the beginning of season 2 and the 1st intro and outro that features Rio Sakurline)

(From S2 EP 25 through S2 EP 30, all 5 of those episodes are full of non-stop funny scenes that would make someone laugh their ass off.)

3rd Terira and Mayo Attack (S2 EP 31)

(S2 EP 32 is a episode that doesn't really have much of an arc happening.)

Necropolis High Traitor Arc (S2 EP 33 to S2 EP 36)

(S2 EP 37 through S2 EP 43 are all episodes about character backstories.)

(S2 EP 44, 45 & 46 are the 3 episodes that lead up to the ACTUAL war arc.) (Same intro as early season 2 but with different visuals)

Rio Sakurline War Arc (already mentioned here) (S2 EP 47 to S2 EP 64) (New intro and outro for the war arc) (EP 53 to 64 have a different intro and outro than from EP 47 to 52).

Mourning Arc (S2 EP 65 to 72) (new intro and outro)

Rebuilding Arc (S2 EP 73 to 84) (same intro as the Mourning Arc but with different visuals and the beat is slightly faster.) The Outro of this arc is a quieter and more muffled version of the 1st outro from the start of season 1. (End of season 2)

Aaron & Liza Intro Arc (S3 EP 85 to 86) (new intro and outro cause start of season 3)

Memorial Arc (S3 EP 87 to 89)

Faye Wolfer's Warning Arc (S3 EP 90 to 94)

Faye Wolfer's Plan to prevent another war arc Arc (S3 EP 95 through 99)

The Final Arc (S3 EP 100 through 123) (New intro and outro to represent the theme

Last episode of the Gem of Nostalgia Animated series (S3 EP 124) (Has a good and very impactful, touching ending) (The Ending Theme is a full several minute long song that incorporates parts of the intro themes of all previous arcs)

(Specials, movies, Pilot episodes and thrillers of the series are usually in-between episodes. Like in season 1 one of the specials has a character that's a major character in season 3 but that character is a background character in that season 1 special.)