Biologically I'm a titan but I feel like a hunter. I'm transguardian

My ghost rezd me as a Titan but I feel like a warlock so that's what I am and if you don't respect my identity you're a terrorist.

There are 3 classes, 4 classes, even 5.

What your guardian's class is when you are reborn is determined by what kind of person you were before death. Now before guardians started becoming more organized there were Iron lords they were sort of hybrids, but their character's remained true to their skills. Skills turned into duty and duty turned to what we see today, the loose stalkers of the night, bounty hunters and skilled warriors of arc, being hunters/scouts. Builders and protectors of the last city, mercenaries that choose to follow the sun and mighty arc fisters being inferior. At last the warlocks they think an shit you know..

Its most likely based on personality and behavioral traits. Titans are stalwart soldiers that like structure and order. Hunters are lone wolf rogues and renegades who like to bend the rules and work outside of their constraints. Warlocks are intellectual types who want to learn and study the mysteries of the universe. Jock, rebel, and bookworm. Guardians are based on teenage high school cliques

[quote]1. When your ghost revives you for the first time, how do they determine what class the person they revive is? Does it have to do with previous life personality traits?[/quote] It's determined through your previous life's personality traits. [quote]2. Why can't a guardian change what class he is (I know why outside the game, but in game lore wise)? Say he was revived as a titan but feels like a hunter would suit him better.[/quote] That happened to Osiris, who thought his Ghost made a mistake in bringing him back. You're stuck being a Titan, Hunter or Warlock after you become a Guardian. [quote]3. Why does class determine what specific abilities your guardian has? Are you just locked into a specific ways of thinking in your class that you can't understand what is required to use a different set of abilities? I.E. A titan using dawnblade[/quote] It doesn't. I'll go into more depth of with this answer below. This is going to be a long reply, and there's not going to be a TL;DR, so bare with me: The Traveller is the only source of Light. In Destiny 2, the only way we can recover our Light is from the Traveller's shard. This means that during the The Taken King Subclass missions; IE Sunbreaker, Stormcaller and Nightstalker, we didn't necessarily access the Light from the Forge, Arc Storms and the Black Garden, respectively. We may have accessed Solar, Arc and Void [i]ENERGY[/i] from these sources, but not technically the Light. The Traveller is the only source of Light, that we know of, and accessing this light, as Guardians, allows us to manipulate the fundamental forces of our world; IE Arc, Solar and Void energy. When we manipulate these forces and project them into our world, they're often referred to as Solar Light, Arc Light and Void Light. The Grimoire Card for Arc, Solar and Void are pretty clear in defining this. For example, the Arc Grimoire Card reads: [quote]The universe is defined by fundamental forces. Complex matter is bound together by deep forces - and in the study of this binding lies the secret of Arc Light.[/quote] We can use the Light, from The Traveller, to uncover the secrets of these fundamental forces, and by doing so, we can use them as a Weapon; IE Arc Light, Void Light and Solar Light. The Solar and Void Grimoire Cards have the exact same thing. Both cards refer to Solar and Void as fundamental forces, and by understanding these forces, we can discover Solar and Void Light. This is important to understand the new subclasses in Destiny 2. Destiny's history tells us that subclasses can be influenced by energy sources, for example, Stormcallers learn the technique from studying Arc storms, a source of Arc energy. The 'Bottle the Arc' questline in Destiny 1 reads; [quote]"The Vex of Mars seek out Arc energy storms that race across the planet. Find a storm. Meditate. Observe the lightning's flow. And master it." - Ikora[/quote] In this case, the source of energy, IE Arc Storms - a fundamental force of our world, influences the creation of the subclass. The new classes in Destiny 2 are modifications and improvements upon previous Light manipulation techniques. I think it's important to understand that when we are born as a Guardian, we don't instantly become a Striker, or a Nightstalker or a Voidwalker. You have to learn how to use the Light - Light from The Traveller, to manipulate the fundamental forces of the Universe. Essentially, that is the role of the Vanguard. The Vanguard teach you these techniques. The Vanguard are very competent in different ways of using the Light to harness the energies Void, Solar and Arc. In every subclass quest line, in every class, Titans, Hunters and Warlocks, there is a heavy focus on mastery - mastering techniques that use the Light. For example, the Striker Titan questline reads: [quote]Stormcallers and Bladedancers have mastered respectable uses for Arc Light. Their Arc Light strikes many times until their foes fall, but a Titan's lightning strikes only once. Once is all we need.[/quote] The golden Gun questline reads: [quote]There are plenty of Gunslingers doing the Tower's work, but only a rare few reach your level of mastery. That's some damn impressive work, Guardian.[/quote] And as you get better at wielding the Light, at using the Light, the Vanguard continue to push you, to develop your techniques. Essentially, your Guardian creates their own subclass as an improvement to the previous; Sentinel from Defender, Dawnblade from Sunsinger. Your Titan wouldn't want a Hunter's abilities, because (s)he would probably prefer to create his/her own.

Hunters learned to blink from locks... the classes normally don't use other classes abilities, because of how each one views as the way to wield the power of the light. You can see locks always letting the light flow through them in it's natural state, you can see hunters use the light as a weapon/tool, and Titans a mix between the two.

I don't think the classes are that strict in the lore. I'm pretty sure a new guardian isn't in a particular class until they get to the city and join an order. There are exceptions to this of course. For example, our guardian immidiately showed signs of a class. I think our abilities depend on how we train and focus our light. Different classes have different abilites because they are taught most of their abilities from their order or mentors. There have been cases where a guardian learns an ability from another class. An example of this is when Felwinter learned how to shoulder charge(even though he's an established warlock). I believe it's entirely possible for guardians to change classes. It would be incredibly rare, but it is possible. An, example is how Rezzyl essentially became a hunter.

And why do Arc Striders have a staff instead of something that makes sense?

Based on the fourth question, I'd say you are a Warlock, like me.