I've currently written a crossover between Shingeki no Kyojin and Fate/Stay Night and one reviewer pointed out that there was a sword, Eckesach, that had the concept of killing giants. I've looked it up in the internet and I've found no results about this. However, if this sword does exist, then I would like to know its history, just so I can consider making it a possible addition to Shirou's Unlimited Blade Works. Does anyone have any information about this?