Diego López IV de Haro
Diego López IV de Haro( died 1289) was a Spanish noble and the Lord of Biscay from 1288 to his death in 1289.
Lope Díaz II de Haro
Lope Díaz II de Haro Cabeza Brava (b. 1170 – d. 15 November 1236) was a Spanish noble of the House of Haro, the sixth Lord of Biscay, and founder of the municipality of Plentzia.
He was the eldest son of Diego López II de Haro and his wife, María Manrique.
Lope was also a member of the Order of Santiago.
Violant of Castile
Violant of Castile( 1265–1287/1308), infanta of Castile and Lady of Biscay on her marriage to Diego López V de Haro.
She was the daughter of Alfonso X of Castile, and Violant of Aragon.
Teresa Díaz II de Haro
Teresa Díaz II de Haro( born before 1254) was a Spanish noble woman and a lady of Biscay, and one of five children of Diego López III de Haro, the Lord of Biscay, and Constanza de Bearne.
Her maternal grandparents were the viscount Guillermo II de Bearne and his wife, Garsenda de Provenza.
Her paternal grandparents were Lope Díaz II de Haro, also Lord of Biscay, and of Urraca Alfonso de León, the illegitimate daughter of King Alfonso IX of León.
Amongst her siblings were Diego Lopez V de Haro and Maria II Diaz de Haro.
María Díaz I de Haro
María
Díaz I de Haro" the Good"( b. 1254–1342) was a Spanish noblewoman of the House of Haro.
She was the daughter of Lope Díaz III de Haro who was assassinated by order of the king at Alfaro, La Rioja.
She is best known for being the Lady of Biscay and for her lifelong battle against her uncle, Diego López V de Haro for the title of the lordship of Biscay.
John of Castile, Lord of Valencia de Campos
John of Castile," called the" el de Tarifa( 1262 –25 June 1319) was an" infante" of Castile and León.
He was engaged in a decades long fight for control over the Lordship of Biscay with Diego López V de Haro, the uncle of his wife.
Diego López (footballer, born 1992)
Diego López( born 19 May 1992) is an Argentine professional footballer who plays as a defender for Gimnasia y Esgrima( J).
Lope Díaz de Haro (d. 1322)
Lope Díaz de Haro( b.?- d. October, 1322) was a Spanish noble of the House of Haro, the traditional Lords of Biscay.
He was the firstborn son of Diego Lopez V de Haro, Lord of Biscay.
Whilst he did not inherit his father's title of Lordship over Biscay, he is best known for being the lord of Orduña- Urduña and of Balmaseda.
He further served as Alférez to King Ferdinand IV of Castile.
Diego López III de Haro
Diego López III de Haro (b. ? – d. October 4, 1254, Bañares).
Was the eldest son of Lope Díaz II de Haro and of Urraca Alfonso de León, the illegitimate daughter of King Alfonso IX of León.
Diego succeeded his father as the Lord of Biscay between the years 1236 and 1254.
Fernando Díaz de Haro (Lord of Orduña and Balmaseda)
Fernando Díaz de Haro was a Spanish noble of the House of Haro.
He was the second born son of Diego López V de Haro, the Lord of Biscay, and his wife, the infanta Violante de Castilla y Aragón, daughter of Alfonso X of Castile.
Fernando became lord of Orduña and Balmaseda in 1322, after the death of his brother, Lope Díaz IV de Haro who died without leaving any descendants.

Question: Who is Diego López Iii De Haro's paternal grandfather?