Light aircraft pilot reported a near collision on the runway at EFK when another light aircraft landed downwind while he was taxiing down the runway.

Narrative

Winds 5-8 kts. At 180. Dry pavement. Mostly clear sky with few clouds at 1-2 thousand feet AGL. The other aircraft that had been around earlier had been landing and taking off on 18 because of wind favoring that runway. There were no planes around when I went to practice my ground handling in the biplane. My plan was to taxi around airport; and do 2 or 3 fast taxi runs down Runway 18; exit at E taxiway to return on parallel taxiway for another run. Announced on CTAF that I was crossing approach end of 23 each time. Announced clear of 18/36 each time. Announced entering runway and fast taxi each time. I said; 'Staying on the ground'. On the last run down Runway 18; because it had been so unusually quiet on the CTAF; I called 'radio check' before entering Runway 18. I heard a reply that my radio was 'loud and clear'. I proceeded to fast taxi down 18 and; after each slow down; I did an S-turn to clear the runway for the next fast taxi. On my 3rd and final fast taxi of this trip down Runway 18; when I S-turned just before applying pull power; I glimpsed strobe lights about 150 yards in front of me. I moved immediately to the right side of the runway and stopped. A light aircraft had landed on Runway 36; with the wind; made no calls that I heard for downwind; base; or final; and used hard braking to stop before we collided! When I spoke to the Pilot on the ground while he was refueling; he insisted I had done something wrong and dangerous. I asked if he wanted to talk about it to see if there was anything to be learned. He was hostile; angry; and said 'no' several times; finished refueling and left via 36; again with a tailwind. Regardless if I had heard him on the radio or not; there is no requirement to have a radio to operate at this airport in this airspace. One has to see and avoid and be aware that there may be NORDO aircraft around. I cannot explain how another pilot could have landed on this runway; with the wind; and when I was clearly ON THE RUNWAY during his final approach; if not for most of the other segments of his landing. It seemed like he thought because he 'announced' his landing; he had the right to land; even though another aircraft was on the runway? He may have come straight at the runway instead of flying a pattern? Maybe he was really low on fuel? Maybe his head was down looking at the RNAV crosshairs during the approach? I just don't know how he missed my aircraft taxiing down the runway on a perfectly clear day! Why did the other pilot land on a runway when there was another vehicle or aircraft on the runway? How did he not see me on the ground on the runway when he was on final approach; as I was fully two thirds of the runway towards his approach end of Runway 18 when I saw finally him on the runway. I'd not seen him on final nor heard any radio call when I was doing my 1st or 2nd of the 3 fast taxi segments on this run down Runway 18. For my part - I will continue to make incremental radio calls while practicing on the ground. Announcing all crossings of runways; entering a runway for a fast taxi trip to the other end; exiting the runway; etc. Not only will I do S-turns between starts and stops; with my eye down the runway for alignment; but I will also look up skyward in case there is someone landing in the opposite direction. I do wish I could have heard the other pilot's side of the story; but in the moment; he was very angry.I did debrief with others who were listening to the CTAF during the incident. They confirmed that they heard my calls; and they did not hear any calls from the light aircraft until the last call when he was on short final - and that someone had 'stepped on it' with another radio call. The CTAF is used by many nearby fields. The question still remains; if he was looking out of the cockpit and at the runway; how did he miss seeing me AND why did he continue to land with another airplane on the runway heading towards him?