Above the entrance to the castle on the main tower is the Frankenstein coat of arms; a winged helmet placed over a shield and hatchet. The back of this tower is exposed to the elements; a cunning strategy employed by the Frankensteins in case the castle was overrun by intruding aggressors. The enemy would be exposed to projectiles fired from within the castle, therefore unable to gain a foothold in the strategically positioned tower.
In the main courtyard, the remains of the three story tower dominate the castle. The ground floor housed the sentries which placed them in close proximity to the outlining stairwells and grounds in case their forces were needed in an emergency. The first floor was designed as a large lounge and sleeping room for the residents. Up above on the second floor, a fireplace was built specifically to boil liquids that would be used against any intruders. Boiling pitch, hot water and stones were poured through shafts onto aggressors who had penetrated the outer wall. Life in the castle by no means was comfortable or romantic.
The Kappelle, or little chapel is situated in the outer court. Built in 1450, it houses the tombs of the knights, Hans von Frankenstein, Ludwig von Frankenstein, his son Phillip Ludwig and other family members. Sand stone sculptures depict the interred Frankensteins displaying their religious devotion and homage to each other, and a reminder of a legacy that has slipped into the past.
More recently, Radu Florescu, in his In Search of Frankenstein, argued that Mary and Percy Shelley stayed at Castle Frankenstein on their way to Switzerland, near Darmstadt along the Rhine, where a notorious alchemist named Konrad Dippel had experimented with human bodies, but that Mary suppressed mentioning this visit, to maintain her public claim of originality.