The second illustration — Card #02, High-Priestess — among many in a personal Tarot project, where I create the art for the symbolism devised by those who understand decks like the Rider-Waite enough for me to help visualize their ideas. These cards are also inspired by another classic story (Chrono Trigger) that has a cult-following but has largely been forgotten by the mainstream.
For this illustration, in order to bypass the tediousness of managing perspective-lines, I quickly and roughly blocked out a 3D set in Blender, making the chairs and pillars by hand. After this, I drew, inked and painted everything else on top in Krita.