This is not the typical route up Mt Olympus.
This was done only by a handful of people, and is not recommended route. The route starts at the a certain point of Maunawili Demo trail, and climbs straight up to Mt Olympus. The bottom part of the ridge is overgrown with uluhe fern, so that is your first obstacle. After you bushwhack for like 0.4 miles (which doesn't sound much, but it's a lot), you get to the bottom of this hill in the middle of the ridge. The climb up is treacherous. You hit a wall and you have to contour on the right, and find a way up climbing from tree to tree in almost 90 degrees. When you top out the terrain flattens a bit, but gets more overgrown. From here just a short section and you start climbing straight up holding uki grass, clidemia plants whatever you can to ascend. At one point you get to a "lip" like a carving on the mountain side. You keep left on that making your way to the final climb. That is where it gets tricky. I know some other groups needed help from the top to climb up, but we managed to pull ourselves up to the KST (Koolau Summit Trail) without any help.
Made it to the actual Mt Olympus top just under 4h, which was very pleasing.