Same question could be asked about why no Alpha Lupi armor for warlock.

The reason Titans don't have any armor is because they don't. Pretty damn simple, there's no actual evidence to say "only warlocks could kill them" or even "Hunters could only kill babies" that's all half thought out and hollow. What is actually true that will give insight is that ALL (normal, meaning raid excluded) Titan armor is made by the Titans of... i wanna say Firebreak? Pretty sure, so blame them for not making any.

According to the lore,warlocks were the only one who could kill an adult ahamkara, using brains over brawn. Hunters were able to kill them also however they only managed to kill the young ones hence "young ahamkara spine ". Titans while strong, were simply outwitted by the ahamkara.

The ahamkara are great and powerful beasts. Like the queen's harbingers; they originate from the void Their power is vast. Their youngest can fill entire worlds with teeth. Their full grown can burn worlds to nothing but black ruin. And their dire can consume entire realities. Then of course there is their ability to defy extinction itself; merely altering themselves whenever it was necessary. [spoiler]their last known form being that of dragons[/spoiler] We must also remember that the ahamkara's power was not only that of strength and destruction. They had even greater minds. Their solipsistic whispers could flatter any being (And more over control them) if they did not understand the ahamkara or the void. When the guardians first came into contact with them; the sides made deals. It made sense. The city needed power, and the ahamkara could supply it. Though many guardians went after them for differing reasons. Some for power, others for penance, others for vendetta, etc, etc. And those unfit for their minds were turned mad. Killing their fellow guardians, or worse Though they had much more to offer. They had answers to questions no one dared to inquire. Having this revelation, the charlata- I mean speaker, decided they were too dangerous. And so the hunt began. And since we Warlock are more mentally adept; we were given the smoking gun. Whilst those such as titans, and many hunters, were forbade. [spoiler]I'm not saying all titans were not smart enough. Simply a vast majority were not knowledgeable enough to fight[/spoiler] Voidwalkers would hunt the dire, such as nyx, or eao Any Warlock would attack the adults And the smartest hunters were left to dispose of the children. And so... they were all gone Their solipsistic flatteries silenced Their great design, if it even ever existed, destroyed Though skeptics still remain. Some report sightings on venus. Some report an obscure call. Not their ghost, or subconscious. But... something... more Perhaps some survived... Perhaps those who died once again defied extinction... Perhaps they let us win... Though this is all impossible. The ahamkara were dealt with. We won For this, you can be assured... [spoiler][b][u]Oh reader mine[/u][/b][/spoiler]

Because while the Warlocks and Hunters were off playing their little game and thinking they were dragonborn, the Titans were actually fighting the real enemies of humanity. Titans knew which was more important.

Warlock:hey, me and the hunter are gonna go hunt arhumkara, wanna come? Titan: can I punch it? Warlock: well they fly so... no Titan: ok good luck

Because our T-Rex arms cluldnt imagine reaching the flying beast.

No association whatsoever you say... Bones of EAO - Scales of EAO... Coincidence, I think not!

Titans are much too disciplined. They have a codex and a long history for guidance.

Oh um the titans decided to defend the wall surrounding the city while the warlocks were slaying the ahamkara. A large group of hunters were able to take down a baby ahamkara. Warlocks on the other hand could take them down using arcane power single handedly. The titans were noble and fought for the city along with one hunter who tragically died in battle on the outer wall. In his honor they forged the gjallarhorn and used the crest of alpha lupi on his chest as a part of the weapon. By the time the city wall had been fully built it seemed like the ahamkara was extinct because of the great hunt. However it is clear now that they aren't and may preparing to come out of hiding in an epic dlc. Cant wait!

Warlocks had the strength and wisdom to withstand the power of Ahamkaras and go toe to toe with them. Hunters were skilled and cunning enough to outsmart a child Ahamkara, because Hunters were former Warlocks, they could withstand somewhat of the power of the Ahamkaras Titans primary focus was the defense of the city. They were repairing and edefending the walls. In theory, a Titan's might could withstand an Ahamkara, but their intellect was far inferior so they were easily outmatched by Ahamkaras. Titans assisted in the killing of Eao, the info is scarce but Titans managed to contain Eao and anchor it to the ground while Warlocks dealt the killing blow. Proof of this is the Titan Artifact Scales of Eao

I think it's because (please don't hunt me in crucible) Titans are the only ones who haven't killed an ahamkara. I'm not saying you're weak (after all those hammers and electric explosions I've fallen to, how could I?) but it's true. We know warlocks have killed ahamkara's, and the hunter artifact ahamkara's scale, with the item description saying "And that Warlock said I couldn't do it! Ha!" Is an obvious hint that the Hunter killed an ahamkara. Yet absolutely no Titans have confirmed an ahamkara kill, in either grimoire or items specific to them. This could be because they prefer to stick to the walls of the city, and the fact that the only Titans who don't adhere to this are the sunbreakers, and because they're mercenaries and nobody would want a wish making machine destroyed, they wouldn't have been likely to kill an ahamkara either.