oristarA,
"Posing himself" doesn't fit, that is, even though the dictionary definition seems to okay this usage, it's not used this way in idiomatic English. "Positioning himself" might work, "Positioning himself in a threatening manner...". Vivien's suggestions here are better.
"Grinding his knife" is ambiguous because there are other meanings for "grind"... my first mental picture was of a man twisting his knife-point against the table, with an empty bowl indicating his poverty. And "wildly" connotates "crazily, without control" -- you can't sharpen a knife wildly. So it would be better to use a phrase like "He sharpens his knife determinately..."
Also, everyday should be two words here: "...who enjoys big meals every day..." Everyday is an adjective used to modify a noun: his
everyday clothing. Every day is a noun (day) modified by every, meaning each individual day: "eats well
every day"... If you can substitute "each" for "every", use two words. Lots of native English-speakers miss this one, but just because it's becoming more common doesn't make it correct!