This is another of Gwillym Pen Pwyll's stories "Ragamuffin Tales". This one concerns the devil, known as Andras, and a deal he makes with a farmer in Trehafod.

Well, this is another tale that you may not care to believe in, Em. The old rapscallion we call the devil became known as Andras in Wales. On this particular summer’s day, Andras had changed into a raven and perched on an oak tree near the old farm in Trehafod. The farmer struggled to get his harvest in as both his boys had joined Wellington’s army to fight old Bony. He also needed a barn to store the corn because there was so much. Believe me, the farmer felt strange as he espied the raven and knew it as a man in disguise. Then he rubbed his eyes and saw a tall, saturnine gentleman strolling towards him with a limp. What struck the farmer as peculiar was that he could not see his boots. Andras bid him good day and said he could build a barn for the storage of the corn if the farmer would let him own the first person who appeared by the farm gates. All the work, Andras continued, will be completed before the cock crowed the following morning. This offer, he said, is a bountiful gift because he felt sadness for the farmer. The farmer knew this to be wrong, yet he could not refuse the polite, articulate gentleman if he could, as he said, build the barn in one night. Whatever spell Andras had cast on the poor farmer ended when a happy voice called “Here I am, father. I said I would not be too late.”
The farmer’s daughter walked up the steep slope towards her father. How could he be speaking with someone, she thought, when I cannot see with whom he speaks? The farmer, stuck for a retort, stared as Andras turned, fading before his eyes as the farmer saw the cloak lift with the breeze and reveal his cloven left foot. The farmer held his daughter close to him because he was so frightened. What was his going to tell his wife?
Of course, she was furious and called him an imbecile. How could he have been so erring in his ways when the realization should have been he spoke with the devil? When early evening came, the work had started on the barn by Andras’s imps and continued at a tremendous pace. The daughter would not stop crying and, as her mother comforted her, she begun to think of a plan to thwart Andras. There is no possibility he would take their daughter from them.
Dejected, the farmer watched the work from the doorway of the farmhouse. A shooting star appeared in the night sky and he believed this an omen of his impending death once the barn is finished. Whilst her husband and daughter slept, the farmer’s wife crept out of the farmhouse as the work continued on the barn and hid amongst the shadows as she entered the henhouse. Under her cloak, she carried a lantern that so startled the hens and cockerels that they believed it is dawn. She clapped her hands and started crowing like a cockerel. The other birds followed. Outside, Andras bellowed so loudly that it sounded like thunder in the night sky. His imps departed underground and the barn started to collapse as Andras blew his fetid breath on the stones. The noise in the henhouse awoke the farmer and his daughter. They rushed out into the farmyard to see what all the commotion was. The farmer wept tears of relief when he saw that the barn was no more; his daughter was now truly safe. All this happened because of the cleverness of his wife. She would not let the old bugger Andras take their daughter.
The land, where the barn stood, remained fallow for decades afterwards. The reason for this is that the earth was like mud, red and watery.