Comics Titania originated in Secret Wars, a 12-issue limited series where a nigh-omnipotent being from another universe had various heroes (Avenger, Fantastic Four, X-Men, and Spider-Man) and villains fight one another on Battleworld, a planet the Beyonder made from parts of other worlds (including apparently a Denver suburb). It is notable for setting up a few things in continuity back in the day: most notably Spider-Man's black costume which eventually turned out to be a symbiote which then lead to the creation of Venom, but also the Thing taking a sabbatical from the FF and She-Hulk replacing him, Magneto first being identified as "heroic" (as the Beyonder placed him with the heroes rather than villains), the introduction of a new Spider-Woman, and Doctor Doom using local super-science to empower two regular women as Titania and Volcana.
Comics Titania is basically a mirror image of She-Hulk: originally a rather timid lady who gained super-strength and toughness (not to mention height and
the Most Common Super-Power). So of course they become rivals. Comics Titania is also a long-time partner of The Absorbing Man, who showed up in Agents of SHIELD (which makes his MCU version have dubious canonicity).