Are you
A Tenno from Warframe
My true identity was hidden from myself and the world, I am not what I appear.
The player themself does not learn what a Tenno truly is until far into the game, and it is no secret that most of the AI characters in the game do not know either.
"What flesh lies within that Warframe?" -General Sargas Ruk
I'm a master of all weapons and fighting styles, I can adapt to any situation.
A key concept of the game is leveling and "mastering" as many different gear pieces (weapons) as possible
Some worship me, others hate me. I allow legends, myths, and gods to live on.
The Arbiters of Hexis and the colony of Baro Ki'Teer all regarded the Tenno as almost divine beings. Legends of a single Tenno defending a population show up in several places in the game. Meanwhile, the Grineer and Orokin hate(d) them. Also, by you can acquire the warframes Inaros and Harrow, among others, which are relics of others who regarded a legend (by Baro Ki'Teer's colony) and a god (by the Red Veil) respectively.
When I awoke, I took full control and grew stronger so that I might protect the world from coming threats.
"Awakening" refers to a Tenno learning of their true self, and comes with additional powers and abilities. These additional powers are most useful vs a new faction that shows up halfway through the game. A "coming threat."
Who I was created to protect I destroyed. I fight to hold the world in balance.
The Tenno destroyed their creators, the Orokin. The Tenno also routinely redirect their efforts to fighting different factions to keep them "balanced"
My body is a mask, I can change or shed it as I choose.
A Tenno can switch between any acquired Warframes at will