In the region of Awelsia, vengeful Freyja travels with an unknown weapon called "AeternoBlade" to take revenge from Beladim, the Lord of the Mist who destroyed her village, Ridgerode, and killed her tribe. Her vengeance is helped by Vernia, who has as much merit as Beladim. Vernia taught Freyja about the ability of AeternoBlade.
Freyja has to venture in many world dimensions to find how to annihilate Beladim.
A sequel released in October 2019, with a Director's Cut version of the sequel released in December 2020.
AeternoBlade provides examples of the following:
- 100% Completion: Visiting the entirety of every map, collecting all of the relics, and fighting every type of enemy.
- Advertised Extra: Carol appears in promotional art and is featured in the 3DS theme as a major character, but she's already dead at the start of the game and only appears in a flashback and true ending.
- As Long as There Is Evil: Beladim is a byproduct of humanity's collective hatred and lust for vengeance.
- The Atoner: Freyja vows to become this on the true end route, submitting herself to any punishment the Chrono Lord sees fit to inflict upon her, but only after completing her mission.
- Because Destiny Says So: Vernia's excuse for not helping Freyja during the final battle. Of course, the real reason is more than that.
- Chekhov's Gun: Played with. Zevil helps Freyja obtain water from the Fountain of Time. Later, when Freyja herself encounters the Fountain, she says it's no longer needed courtesy of her having gone back in time with the sword still powered up from last time.
- Color-Coded for Your Convenience: Objects that glow green are unaffected by Freyja's time manipulation.
- Deader than Dead: The consequences of going too far back into the past.
- Death Is a Slap on the Wrist: You can choose to continue at the last checkpoint or at the entrance of the screen you died on.
- Downloadable Content: Alternate outfits for Freyja as well as access to Arena Mode.
- The Dragon: The Rain Spirit.
- Dual Boss: The chapter 3 boss along with the true final boss fight against One-Winged Angel Beladim and Vernia.
- For the Evulz: Actually averted. Beladim causes chaos and destruction because doing so increases humanity's collective thirst for revenge, which gives him more power.
- Foreshadowing: Vernia is quite insistent that Freyja succeed in killing Beladim, even telling her to embrace her anger and hatred of him as a weapon.
- Generic Doomsday Villain: Beladim is pretty much this.
- Heroic Sacrifice: Zevil in order to send Freyja back to the past before the destruction of the village, only they can't quite get back far enough, creating the Stable Time Loop. He does get better because of the same loop though.
- If You Kill Him, You Will Be Just Like Him!: Played very, very straight as a plot point and leads to the bad ending if Beladim is defeated in his chamber rather than in the past.
- Leeroy Jenkins: Freyja nearly gets herself killed by Beladim not two minutes into the adventure by blindly rushing him. Had Vernia not taught her Time Reversal, she'd have been dead right away.
- Mirror Boss: Equipping one of Freyja's alternate costumes makes it much easier to keep track of which is which.
- Multiple Endings: A normal ending, bad ending, and true ending.
- New Game Plus: Played with. If the player does not meet Bernard in the Eternal Void and recover his Memory Crystal, the game starts all over, including the loss of Freyja's skills and relics, after defeating Beladim.
- Nigh-Invulnerable: Beladim and the Time Guardians until the AeternoBlade is properly powered up. One Elite Mook can only be killed via Telefrag as noted below.
- One-Winged Angel: The true final boss.
- Out-Gambitted: How Freyja manages to usurp Vernia's AeternoBlade's power rather than be affected by it.
- Puzzle Boss: The Chrono Lord.
- Randomly Drops: Every enemy has a chance at dropping a relic.
- Revenge Before Reason: Zevil tries to talk Freyja out of her revenge. She'll have none of it.
- Roaring Rampage of Revenge: Freyja for her village, of course.
- Stable Time Loop: Averted if the player is not on the true ending path. Part of earning the true ending requires breaking it.
- Telefrag: A type of Elite Mook near the end of the game requires using Time Reverse to trap inside of a special green block (that's not affected by Freyja's time manipulation) to kill it.
- Time Paradox: How Vernia is defeated.
- Timed Mission: The true final boss.
- Timey-Wimey Ball: It's weaponized in this game!
- Tomato in the Mirror: Vernia is Freyja's future self after absorbing Beladim's power and becoming the new Demon Lord.
- The Unfought: Averted with Vernia.
- What Happened to the Mouse?: Invoked, as Freyja deliberately drives Zevil away once she recognizes she's in a Stable Time Loop in order to prevent his Heroic Sacrifice.