Biollante was originally a human girl, Erika Shiragami. The daughter of a lead scientist in genetics,
Doctor Genichiro Shiragami to be exact. However Erika was killed in an explosion, but her soul went into a rose, which Erika was fond of. However, with the work of Dr. Shiragami, the rose soon had Godzilla's DNA spliced into it, thus creating a plant like creature. Biollante's first form appeared as a giant rose. Seeing as it was Godzilla's biological "sister" she drew Godzilla to her, in an attempt to kill the king of the monsters. However, when Godzilla arrived the ensuing battle resulted in Biollante suffering several heat ray blasts from Godzilla transforming her into an immortal creature. However, Biollante regenerated into her final form, a gargantuan abomination. She quickly engaged Godzilla in combat and again suffered a similar fate as before, taking several heat ray blasts from Godzilla, eventually defeating her. After being defeated, Biollante once again transformed into immortal energy, only to return later as part of Spacegodzilla.
Biollante has one of the best regenerative abilities, as the regenerating powers of Godzilla, Plants, and Humans were mixed into one giving her one of the most powerful healing factors in any Godzilla universe. She had the best regenerator until Orga made his appearence in Godzilla 2000. She is also immensely strong and despite her mass of 200,000 metric tons, she is very fast. When she moves she creates earthquakes as the vines she put deep into the earth move, unsettling much of the earth she is on. She can also spit extremely radioactive and corrosive acid sap from either her mouth or her many vine's mouth's with startling accuracy. She has human level intellect, and she retains all the memories of her deceased human form and those of Godzilla. She can also use her impaling vines with such great force that they can penetrate even the likes of Godzilla's hide, In fact they can go straight through his hand. And she never tires as she does not generate fatigue toxins. Overall she is practically impervious to any conventional attack and can overwhelm nearly any physical powerhouse.