Question: Lahamu had a brother who represents what element of Akkadian mythology?

Context paragraphs:
Aya (goddess): Aya (or Aja) in Akkadian mythology was a mother goddess, consort of the sun god Shamash.  She developed from the Sumerian goddess Sherida, consort of Utu.

Sirara (goddess): Sirara, also known as Nanshe, is the goddess of the Persian Gulf in Sumerian, Babylonian, and Akkadian mythology.  In creation mythology she is given charge over the waters of the Gulf by the god Enki, her father.  She also helps the poor, orphans, and widows.  She was born to heal her father's neck after being cursed by his wife.

Lahmu: Laḫmu, Lakhmu, Lache, Lumasi, or Assyro-Akkadian Lammasu is a deity from Akkadian mythology that represents the zodiac, parent stars, or constellations.

Mandanu: Mandanu in Babylonian and Akkadian mythology is a god of divine judgement.  He is known from the neo-Babylonian period.

Lahamu: Lahamu (also Lakhamu, Lachos, Lumasi, or Assyro-Akkadian Lammasu) was the first-born daughter of Tiamat and Abzu in Akkadian mythology.  With her brother Lahmu she is the mother of Anshar and Kishar, who were in turn parents of the first gods.  Lahamu is sometimes seen as a serpent, and sometimes as a woman with a red sash and six curls on her head.  It is suggested that the pair were represented by the silt of the sea-bed, but more accurately are known to be the representations of the zodiac, parent-stars, or constellations.

Ušumgallu: Ušumgallu or Ushumgallu (Sumerian: 𒁔𒃲 "ušum.gal", "Great Dragon") was one of the three horned snakes in <a href="Akkadian%20mythology">Akkadian mythology</a>, along with the <a href="Ba%C5%A1mu">Bašmu</a> and <a href="Mu%C5%A1ma%E1%B8%AB%E1%B8%AB%C5%AB">Mušmaḫḫū</a>.  Usually described as a lion-dragon demon, it has been somewhat speculatively identified with the four-legged, winged dragon of the late 3rd millennium BC.

Ilabrat: Ilabrat, in Assyrian, Babylonian and Akkadian mythology, is the attendant and vizier of the chief sky god Anu and part of his entourage.

Abzu: The Abzu or Apsu (Cuneiform: , ZU. AB; Sumerian: abzu; Akkadian: "apsû", ), also called engur (Cuneiform:, LAGAB×HAL; Sumerian: engur; Akkadian: "engurru" - lit., "ab"='water' "zu"='deep'), was the name for fresh water from underground aquifers which was given a religious fertilising quality in Sumerian and Akkadian mythology.  Lakes, springs, rivers, wells, and other sources of fresh water were thought to draw their water from the abzu.  In this respect, in Sumerian and Akkadian mythology it referred to the primeval sea below the void space of the underworld (Kur) and the earth (Ma) above.

Ishum: Ishum is a minor god in Akkadian mythology, the brother of Shamash and an attendant of Erra.  He may have been a god of fire and, according to texts, led the gods in war as a herald but was nonetheless generally regarded as benevolent.  Ishum is known particularly from the Babylonian legend of Erra and Ishum.  He developed from the Sumerian figure of Endursaga.

Kus (god): Kus is a god of herdsmen in Sumerian, Babylonian, and Akkadian mythology.  He is identified in the "Theogony of Dunnu".

Supporting paragraphs: Lahamu Lahmu
Answer: zodiac