Leprechauns are Sburb constructs that assist dead session players who take the path of the conqueror. Whenever the player successfully conquers and destroys a planet, they are granted a new leprechaun minion with a unique magical power. To achieve victory, the player must learn how to organize their leprechauns into a team and use their diverse powers together to overcome the session's challenges.
The physical appearance of a leprechaun is diverse; however, they all share the same light green skin color. Their skin feels like the felt surface of a billiards table. Their anatomy resembles that of a carapacian. This may be because both species are generated by a Sburb session. Their size can vary from tiny, like Clover, to enormous, like Cans. Their blood is red, as displayed repeatedly in the first intermission. Leprechauns possess a wide variety of different magical abilities.
Leprechauns have a complex system of romance consisting of nine charms. One of these corresponds to the concept of romantic love as known by both trolls and humans, the other eight charms are related to this by a continuum of relationships established by pranks, riddles and games of chance. Unlike the quadrants, instead of attempting to have only a single relationship with another individual per quadrant, leprechauns strive to share as many charms with their partner as possible, with a pair sharing three or more charms being called a trove.
Certain combinations of charms are more conducive to reproduction than others. Reproduction involves an elaborate coupling followed by a lively mating jig, with the jig in question being defined by the charms involved. While Aranea's exposition on the matter was interrupted, of her lecture posted by Andrew Hussie confirms that the species reproduces homosexually. The rest of the lecture, a graphic description of the reproductive process, is covered with glitches and rendered unreadable except for a few phrases, the majority of which quote or otherwise reference Dave's remarks from earlier in the story, regarding his Bro's smuppets.
According to Aranea, most of their culture and customs revolve around luck. She fails to go into any greater detail, becoming sidetracked by leprechaun romance.
- The romantic charms resemble the symbols used in Lucky Charms cereal, which features a leprechaun as its mascot. The first boxes of Lucky Charms cereal contained marshmallows in the shapes of pink hearts, yellow moons, orange stars, and green clovers. The lineup has changed occasionally over the years, beginning with the introduction of blue diamonds in 1975. Purple horseshoes joined the roster in 1984, followed by red balloons in 1989, rainbows in 1992, and pots of gold in 1994. Many of these charms have been replaced or altered in today's boxes of Lucky Charms.
- The update explaining leprechauns occurred one day before Patrick's Day, which is an Irish holiday. Considering leprechauns are a type of fairy in Irish folklore, this was most likely intentional.
- A combination of charms (star-heart-horseshoe) has shown up three times in MSPA, the being in Problem Sleuth. They are never mentioned as charms in Problem Sleuth as leprechauns had never been introduced. The second appearance is when Dream Jade sets her wardrobifier to said sequence . The third time is in a conversation between Caliborn and Hussie wherein Hussie says that Caliborn should try a star-heart-horseshoe
- The existence of leprechauns, as well as cherubs was foreshadowed during Hussie's rant on .