Who is Lu referring to?

Lu Jianzhi (A.D. 1045- 1 105). Jiangsu Wuxian (now Suzhou) people. Guan Yu rushed to Shi Wen Shu Ba. Lu Jianzhi studied books with his uncle when he was young. His uncle was Yu Shinan, a famous calligrapher at that time. Learning the "two kings" is late, "writing is muddy, ashamed to fly beautiful style", and calligraphy has the reputation of "being good at blue late" Handed down from ancient times, The Preface to the Collection of Five-character Lanting and Lu Jianzhi Shu Wen Fu have the best ink marks. Among them, the latter is a paper-based ink scroll, which is one of the rare masterpieces in the early Tang Dynasty. This is a work written by Lu Jianzhi. Because "Wen Fu" is a masterpiece of Lu Ji's painstaking efforts, and Lu Jianzhi is a descendant of Lu Ji, Lu Jianzhi wrote "Wen Fu" with great reverence. It is said that Lu Jianzhi fell in love with Lu Ji's Wen Fu when he was young. He has always wanted to write an article by himself. Because I was afraid of my poor handwriting, I "humiliated" my predecessors' masterpieces, but I never dared to write rashly. It was not until his later years that the topic was brilliant that he began to write this old wish. Look at the pen and ink in Lu Jianzhi's books and prose, just as Lu Ji's prose said: "Cage heaven and earth in shape, frustrate everything in the pen", escape gas and brush, catch up with the "two kings".