No, not all Titans are human. In the context of mythology, Titans were a race of powerful deities who predated the Olympian gods in Greek mythology. In the context of popular culture, such as in the anime "Attack on Titan," Titans are depicted as giant humanoid creatures that are not human. Therefore, Titans can be both human and non-human depending on the specific mythology or fictional universe in which they are portrayed. **

No, not all Titans were killed. While many Titans were defeated and killed during the Titanomachy, some Titans managed to survive and were imprisoned in Tartarus. The most well-known surviving Titans include Prometheus, Atlas, and Epimetheus. These Titans were spared by Zeus and were not killed in the war against the Olympian gods. **

Titans eat humans because they have an insatiable hunger for human flesh. In the world of Attack on Titan, Titans are depicted as mindless creatures driven by their instinct to consume humans. The exact reason for this behavior is not fully explained in the series, but it is suggested that Titans may eat humans as a way to sustain themselves and satisfy their relentless hunger. Additionally, some theories suggest that Titans may be driven by a subconscious desire to regain their lost humanity by consuming humans. **

The Titans were not photographed because they were mythical deities from ancient Greek mythology, not real beings that could be captured on film. The Titans were believed to be powerful primordial gods who ruled the universe before the Olympian gods, and they were often depicted in art and literature rather than being physically captured in photographs. Additionally, the concept of photography did not exist during the time when the stories of the Titans were first told. **

Marley can transform into Titans because they possess the ability to inject themselves with Titan serum, which triggers a transformation into a Titan. This serum contains the spinal fluid of a Titan, allowing Marley to gain the Titan's abilities and powers. By injecting themselves with this serum, Marley can transform into different types of Titans, each with unique characteristics and strengths. This ability gives Marley a significant advantage in battle and allows them to wield the power of Titans to achieve their goals. **

Yes, in Greek mythology, Gaia is considered to be one of the Titans. She is the primordial goddess of the Earth and is often referred to as the mother of all life. Gaia is also the mother of the Titans, who were the first generation of divine beings in Greek mythology. Therefore, Gaia is closely associated with the Titans and is considered to be one of them. **

The 9 Titans were created when Ymir Fritz, a figure from Eldian mythology, came into contact with the source of all organic material, known as the "Founding Titan." This contact granted Ymir the power of the Titans, and she became the first Titan shifter. Over time, Ymir's powers were divided among 9 individuals, each inheriting a specific Titan power. These individuals became the original 9 Titans, and their powers have been passed down through generations within the Eldian people. **

In the world of Attack on Titan, people transform into Titans through a process involving the injection of Titan spinal fluid into a human. This injection triggers a transformation, turning the human into a mindless Titan. However, there are also special cases where individuals can transform into Titans without the injection, such as the Titan shifters who have the ability to transform at will. The process of transformation is a central element of the series and plays a significant role in the story's plot and character development. **