The pale yellow flesh changes to different colours when broken or bruised depending on age; younger mushrooms become reddish, and older ones additionally take on bluish tones.

Elias Magnus Fries and Christopher Theodor Hök first described this species as Boletus torosus in 1835, a name by which it came to be known for many years.

Modern molecular phylogenetics shows that it is only distantly related to Boletus edulis—the type species of Boletus—and it was duly placed in the new genus Imperator in 2015.

[6][a] Fries reported in his 1838 book Epicrisis Systematis Mycologici seu Synopsis Hymenomycetum that he had not actually observed the species,[7] and he did not designate a type specimen or illustration.

[19] In 1996, Czech mycologist Jiří Hlaváček further subdivided the section Luridi, defining and naming the subsection Torosi—for B. torosus—to contain boletes that strongly bruised blue-black with handling.

[20] In a molecular analysis of Boletaceae phylogeny, the brawny bolete was most closely related to Boletus luteocupreus; these two species formed a clade that was sister to B. luridus.

[23] Quite heavy compared with other mushrooms of similar size, the stocky fruit body contains relatively high amounts of chitin.

Hemispherical when young, it extends and flattens into a convex and finally a flattish shape, sometimes forming a slight depression in the centre.

Initially curled downward and inward, the cap margin gradually turns outward, eventually flattening in maturity, and sometimes protruding beyond the pored undersurface.

The surface has a mesh-like pattern (reticulation) that has a colour development similar to that of the cap: initially yellow, then purplish, and finally dark brown.

[25] The Mediterranean species Boletus poikilochromus somewhat resembles I. torosus, but can usually be distinguished by a smaller fruit body, a cylindrical stipe, and the lighter colours of younger mushrooms.

[16] Like many boletes, Imperator torosus causes gastrointestinal symptoms such as abdominal pain, diarrhoea, and vomiting when eaten raw.

[27] Coprine ingestion results in heat and flushing in the face, tingling in arms and legs, nausea and vomiting, and increased heart rate within five to ten minutes of consuming alcohol.

They concluded that the most likely explanation for historical poisoning incidents was a misidentification of I. torosus with Suillellus luridus, though they could not rule out the latter species containing a hitherto unidentified compound causing alcohol-related reactions.

[30] Similarly, it is on the list of protected species of macrofungi in Montenegro,[31] and Italy, where it has a highly restricted range and is considered threatened by changed forest fire intervals and habitat degradation.