5. Why Did Starfire Land So Close To The Haunted House?
It's surely no coincidence that Starfire landed so close to the haunted house; presumably she either knew all about it when she arrived on Earth, or her sensors detected a potential dimensional breach and she chose to land nearby.
4. How Did The Tamarans Know What Would Happen In The Future?
Titans has already subtly blended the Tamarans with the "Ancient Aliens" trope, suggesting these aliens were actually the Sumerian gods. In keeping with that, they appear to have the ability to foretell the future, and Starfire produces holographic prophecies showing the death of her entire world should Trigon be unleashed. The "Death of Worlds" book appears to be written in Starfire's language, so is presumably an ancient book of prophecies that fits with the more recent visions of the future.
Related: DC's Titans Trolls Nightwing Fans
3. Why Did Starfire Lose Her Memory?
"Koriand'r" avoids answering one simple, basic question; why did Starfire lose her memory in the first place? Starfire's amnesia is just a convenient way of drawing out the plot, but the fact it's completely unexplained makes that pretty glaring. Even a throwaway comment like "Trigon's servants found me, and he did something to me" would be better than nothing. Hopefully there'll be some sort of explanation next week.
2. What Are The "Trials" Raven Must Endure?
It seems Raven is the only one who can defeat Trigon, and banish him from this dimension. In order to do so, however, she must first complete 400 consecutive days of warrior training - an experience that apparently none have survived. This is a very strange comment, as it suggests others have tried this kind of extensive training and died. Does that mean others have trained to stop Trigon in the past, and failed? If so, it may mean Raven is just the demon's latest attempt to break through into our dimension.
1. Why Did Trigon Let Dick Grayson Into The Haunted House?
The episode ends with the haunted house allowing Dick Grayson entry. He's the only one it lets in, though, so this is clearly a trap. It seems that Trigon's plan is to break Raven's heart by forcing her to choose between her parents and the inconsistent father-figure. While this does indeed work in terms of the show's overall structure, it makes the fact Raven didn't instinctively reach out to Dick for help all the stranger; that would have been a perfect opportunity for Titans to showcase how important Dick is to her, setting this plot up.