Battle Goddess

Long ago in the world of Dir Lifyna, a war took place between two pantheons of gods. When the dust settled, the old order of the Ancient Gods was no more, leaving the victorious Present Gods to enjoy their newfound prominence. But though the war had ended, the conflict continued; even after an age has passed, the Present Gods work tirelessly to root out the remnants of Ancient God worship, surviving Ancient Gods nurse their resentment and hunger for vengeance, and the myriad demons and fiends seek to gain an advantage however they can.

Celica Sylphil, the immortal warrior known as the Godslayer, once battled the goddess Astraea and won, and now lives within her stolen body. While this grants him immense power, it has also made him the enemy of most of the continent; the Ancient Gods hate him for killing one of their own, the Present Gods see him as a threat to their dominance, and the demons now see Astraea's legacy as up for grabs to anyone with the strength to take it. Finding sanctuary in the kingdom of Rewinia - a nation whose list of foes rivals his own - Celica now stands against anyone and anything that would threaten his new home.

Battle Goddess (Ikusa Megami)) is a series of hentai RPGs by the Japanese software company Eushully. There are currently four games in the series. Battle Goddess and Battle Goddess II are two of the company's oldest games, and concern the efforts of Celica and his allies to defend Rewinia from its enemies. The other two games are prequels: Battle Goddess ZERO tells the story of how Celica first became the Godslayer and the immediate aftermath, while Battle Goddess VERITA fills in the remaining space between Zero and the first game, while also crossing over with Eushully's Princess General series.

Battle Goddess provides examples of:
 * Action Girl -- Given that it's an H-game, the vast majority of the party members are female, making this trope automatic.
 * Brainwashed and Crazy --
 * Blood Knight -- Haishera, one of Celica's oldest allies, is a major antagonist for most of Zero. Why does she want Astraea's body? So she can pick fights with even stronger enemies.
 * Chick Magnet -- Celica.
 * Chronic Hero Syndrome -- Celica, before he became the renowned Godslayer. After that, he's more concerned with staying hidden and under everyone's radar.
 * Coup De Grace Cutscene -- After losing a boss fight in Zero, there's a brief follow-up scene in which Celica's enemy finishes him off.
 * Did You Just Punch Out Cthulhu? -- Celica is usually the one tasked with defeating gods, demon gods and other all-powerful beings.
 * Elemental Rock-Paper-Scissors -- Taken to extremes in Zero and VERITA. There are a dozen different "elements" of weapon and armor in the game; all weapons do a certain percentage of their base damage based on the element of their target. The developers included a grid chart (accessible ingame) showing the hundred-odd possible combinations for easier reference. Of course, that doesn't factor in that there are different ranks of each element as well...
 * Equippable Ally -- Haishera is introduced as this; it isn't until Zero that we see much of her outside of the sword.
 * Grand Theft Me -- Basically the premise of the series. Inverted in Zero and the end of BG 2, where we see.
 * Played straight by Haishera in Zero.
 * Heroic BSOD -- Celica post-bodyswap in Zero, after
 * Also Ekria at the beginning of VERITA. This takes place shortly after Princess General 2, where she was the main antagonist, and which ended with her  For a while, the only reason she follows Celica around is the hope that he'll kill her.
 * Celica, again, this time in VERITA, just after
 * The Jailbait Wait -- Explicitly stated in BG 2 as the reason Celica still hasn't performed the ceremony to officially make Saria one of his apostles. Since the procedure arrests the apostle's aging process, he wants to let her grow up a bit more first.
 * In an apparent retcon, VERITA averts this by apostle-cizing Suri when she's still a little kid (her original appearances in BG 1 and 2 had her apparently in her late teens).
 * Lady of War -- Revia, although she's often not very ladylike around Celica.
 * Late Arrival Spoiler -- Throughout Battle Goddess 1 and 2, Astraea is treated as a force resentful and possibly hostile towards Celica, given that he stole her body and must constantly fight to keep it from reverting to its original female form. It's only at the end of the second game that  Given the nature of H-gamers to gravitate towards newer titles, more people have played Zero,
 * "I Know You're in There Somewhere" Fight - Satia tries this on Celica. It works
 * Laser-Guided Amnesia -- Celica. After certain key events, he forgets everything regarding who he is, who he's come into contact with, and what has transpired over the past x years.
 * Ninja Maid -- After establishing himself in Rewinia, Celica lives with his circle of loyal apostles. They're in charge of housekeeping, so they wear maid outfits... and then continue wearing them, even when venturing with Celica into monster-infested dungeons. Although Ekria, Suri, and Saria are magic-users without notable combat skills, the ex-thief Marinia uses metal claws to great effect.
 * One-Man Army -- In an attempt to retrace his steps and find out what happened to him, Celica
 * Rapid Aging -- When he pushes himself too far trying to capture Celica,
 * Reincarnation Romance --
 * Also played with in that due to Celica being immortal, only one partner is dying and returning.
 * Stalker with a Crush -- Abirus. Who has been to hell and back, chasing "his goddess".
 * The Lancer -- Haishera, after the events of Zero.
 * Token Mini-Moe -- Naberius, Rifia, Suri (who was retconned into being a loli in VERITA).
 * Tragic Hero -- Celica's entire reason for wanting power is to protect those weaker than him. He gets that power, but at a severe price, and now everyone is trying to kill him, physically or otherwise.
 * Tsundere -- Revia. Justified in that it's hard to keep up appearances as a leader if you're constantly being saved.
 * Ekria, for the first few chapters of VERITA.
 * Silk Hiding Steel: -- Ekria.
 * Also Satia.
 * Video Game Cruelty Potential -- During Zero. While is using Astraea's power to wage demonic war across the northern countries, you're given the opportunity to take one nation's princess hostage. Your options range from treating her as an honored guest... to having her repeatedly raped by monsters until her will is broken, then turning her into stone. Yeesh.