Oni is a full-body circuit named after the horned demons of Japanese folklore - the club-wielding ogres that guard hell's gates and test anyone who wants past them. The gauntlet runs: 10 climbers, 2+ basic burpees, 10 knee-to-elbow, 10 shoulder taps, 10 side shoulder taps, 10 bicep extensions and 10 squat jacks. It starts on the floor, ends in the air, and asks questions the whole way.

The circuit front-loads its demons: climbers and burpees are the two most metabolically expensive movements here, and they hit first, spiking your heart rate before the standing work begins. The 2+ on the burpees is an open invitation - two is the toll, everything above it is you volunteering. Knee-to-elbow keeps the heart rate high while shifting the work to your obliques, and then the three-part standing arm block - shoulder taps, side shoulder taps, bicep extensions - grinds your deltoids through three angles of self-resisted work with no rest between them. Squat jacks close the circuit by returning to explosive leg work on a body that thought the hard part was over. Like any proper oni, the workout saves one last swing of the club for the exit.

Keep hips low and level through climbers - speed means nothing if your hips are piking skyward. Make each burpee full and honest: chest low, complete stand at the top. In knee-to-elbow, drive the knee up to meet the elbow rather than crunching the elbow down. Through the arm block, keep tension deliberate - clenched fists, controlled arcs, arms at height. In squat jacks, land wide and low with your weight in your heels, arms overhead as shown.

In the old stories, you cannot sneak past an oni. You go through. Same rule here.

Make it Harder: Make the burpee station 5+ and honor the plus sign.

Make it Easier: Step your squat jacks out wide instead of jumping them.