Few hip-hop artists have the audacity to name a tour “Keep It Irish.” (Even fewer rappers would name a series of albums Love Potion.) In a genre where middle fingers are as common as handshakes, Kansas City rhymesayer Mac Lethal seems to have elevated his single digit above the rest. Tics and all, Mac rhymes with guerrilla disregard for standard operating procedures and expectations. He’s the embodiment of hip-hop iconoclasm, with a heritage (Irish) and a fondness for Everyman topics (love, beer) that further distance him from hip-hop’s mainstream. That all probably matters naught to Mac, whose underground following represents in droves. This performance at the Riot Room, part of his Keep It Irish Tour, should be no exception. The former Scribble Jam champ is emerging from a six-year hiatus from formal battling to compete in the next jam in Miami. Despite the layoff, a clip distributed on YouTube featuring one of his battles shows the wiseass in formidable fighting shape.