Marie

Name: Marie

Species: Mermaid-type Xenos (monster with self-awareness)

Gender: Female

Age: 14

Affiliation: Xenos community (including Lido and Gros)

First Appearance: Main story, Volume 12

Anime Voice Actor: Saya Fukuzumi

Location of Activity: Deep Floors of the Dungeon, mainly the Water City labyrinth and the 27th floor hidden village

Role: Lookout/guardian of the Xenos’ hidden settlement; healer and support for Bell Cranel

Marie is a mermaid whose lower body is that of a fish, while her upper body is that of a beautiful human girl.

Unlike ordinary mermaids in the Dungeon, who tend to have grotesque, inhuman appearances, she is described as a genuine beauty above the waist and looks almost indistinguishable from a human girl.

Her figure is notably voluptuous, especially her chest, which stands out even among the series’ heroines.

When Bell Cranel first meets her, she is not wearing any clothing on her upper body, which leaves him flustered and unsure where to look.

After noticing his embarrassment, Marie responds in her own innocent way by crafting a makeshift bra from thread and seashells and begins wearing it.

Her total length, including her tail fin, is given as 190 cels (in-universe height unit), which makes her comparable in overall size to even large male characters, though this measurement includes the full length of her tail rather than just her upper body height.

Marie’s personality is even more childlike than Wiene’s, with a way of speaking that feels simple, innocent, and somewhat clumsy.

She comes across to Bell as having a weak sense of self, almost like a spirit with a vague, floating presence rather than a grounded person.

She is extremely curious about the world and people around her.

Because she cannot leave the water labyrinth and is often left alone while the other Xenos travel, she is starved for contact and easily grows attached to those who show her kindness.

Despite her innocence, she is emotionally sensitive and reacts strongly to Bell’s gentle behavior and bravery.

Being princess-carried by him and seeing him protect her from the moss giant that terrified her leaves a deep impression and quickly blossoms into clear affection and admiration.

Marie shares the standard traits of mermaids in the Dungeon: a hypnotic charm and superb mobility in water.

She can move underwater even faster than ordinary mermaids, to the point that other aquatic monsters cannot catch her.

Like other mermaids, she possesses a natural charm ability that can enthrall weaker, lower-ranking monsters.

This charm allows her to manipulate lesser creatures when needed, giving her some control over the surrounding ecosystem.

Her most extraordinary trait is the miraculous healing power contained in her blood.

Mermaid blood in this world has a restorative force comparable to the legendary healing properties of a unicorn’s horn.

When Bell drinks Marie’s blood directly, his stamina and vitality are restored to full, even after severe exhaustion.

If her blood is applied directly to a wound—such as by letting the wound “drink” it—it can reconnect severed limbs, as demonstrated when she helps reattach Bell’s right arm after it is cut off by the Juggernaut.

This healing ability is so potent that it does not stop at closing wounds, but can regenerate destroyed parts and restore combat readiness in a very short time.

Because she is a Xenos, her healing and movement capabilities are superior even to those of normal mermaids, making her a rare and invaluable ally, especially in the harsh environment of the Deep Floors.

Meeting Bell Cranel

Marie first appears in Volume 12 of the main story during Bell Cranel’s expedition into the Dungeon’s Deep Floors.

When Bell is separated from his companions and reaches the 25th floor, he is forced to battle a swarm of powerful flying monsters with only a knife.

Watching from the water, Marie witnesses Bell’s desperate but brilliant single-handed fight.

Moved and excited by his display of strength and determination, she spontaneously applauds him, which leads to their first encounter.

First Healing and Growing Attachment

Upon meeting, Marie immediately makes a startlingly bold move.

She bites her own index finger, then presses it directly into Bell’s mouth so he can drink her blood and recover from his injuries and exhaustion.

This direct and intimate gesture reveals her straightforward, uninhibited nature and her lack of embarrassment.

Bell’s kindness and gentle demeanor toward her, combined with his obvious discomfort about her nudity, leave a warm impression on her.

Afterward, Marie crafts and wears a bra made of thread and seashells to ease his discomfort while still not fully understanding human modesty.

When Bell later princess-carries her and defeats the enhanced variant of the moss giant that had been terrifying her, her feelings of trust and affection deepen significantly.

Support During the Juggernaut Crisis

Marie is present during the appearance of the Juggernaut, a terrifying Dungeon monster that drives Bell and his allies into a desperate battle.

During the fight, Bell has his right arm severed, placing him in dire peril.

Marie rushes to help and uses her blood as a last-ditch measure.

By letting his severed arm “drink” her blood and coating the wound with it, she successfully reattaches the limb and restores its function.

From that point on, she repeatedly offers Bell her blood whenever he is pushed to the brink by the Deep Floors’ hardships.

Her continued support allows him to keep fighting far beyond what would normally be possible, making her a critical, though often unseen, contributor to his survival.

Role as Guardian of the Xenos’ Hidden Village

Because her lower body is that of a fish, Marie cannot move freely on land and is effectively confined to the watery labyrinth known as the Water City.

This physical limitation prevents her from accompanying the Xenos and Bell on surface excursions or broader journeys.

Instead, she stays in the depths, particularly around the 27th floor where the Xenos’ hidden settlement is located.

There she takes on the role of “lookout” or “guardian” of the village, watching over the area and serving as a first line of support if danger approaches from within the Dungeon’s waterways.

Although this means she spends much of her time alone, she bears the responsibility with her characteristic innocence and cheerfulness.

Her longing to see her friends again and to have visitors makes her especially welcoming and open to Bell, who treats her not as a monster but as a girl and a comrade.

Bell Cranel

Bell Cranel is the first human to show Marie genuine kindness and respect, which quickly makes him very special to her.

She is impressed by his courage, his willingness to risk himself for others, and his gentle, flustered reactions to her presence.

The moment he princess-carries her and defeats the monster that frightened her becomes one of her most cherished experiences.

Her affection for him becomes clear through her eagerness to help, even when it means injuring herself repeatedly to provide blood for his recovery.

To Bell, Marie is both a lifesaving ally and a reminder that monsters can be as gentle and vulnerable as humans.

Their bond strengthens his resolve to protect the Xenos and to bridge the gap between humans and monsters.

Lido and the Xenos

Marie is part of the same Xenos community as Lido and Gros.

While they travel and fight on land, she stays behind as their aquatic support and guardian of the hidden settlement.

She trusts Lido and the others deeply and looks forward to their return whenever they leave the village.

Her role complements theirs: they defend the group in the wider Dungeon, while she protects their home and offers healing when they are in her reach.

Marie’s age remained unknown for a long time in the original novels.

It was finally revealed during the anime adaptation, where her official profile confirmed that she is 14 years old.

This makes her the first heroine to be the same age as Bell Cranel.

Although another heroine of the same age appears earlier, that character is later revealed to be a transcendent being and is therefore not counted in the same “ordinary girl” category.

Her stated height of 190 cels (including her tail) puts her overall length on par with some of the series’ largest men.

However, since this measurement includes her tail fin, her upper body alone is not quite as towering as the number might suggest.