Ether 10:5-7 describes the reign of Riplakish. Note how his wickedness was duplicated by wicked King Noah (see Mosiah 11). The following are characteristics of both kings:
Characteristics Riplakish Noah
Very immoral Ether 10:5 Mosiah 11:2
Taxed the people heavily Ether 10:5 Mosiah 11:3
Built spacious buildings Ether 10:6 Mosiah 11:8
Glutted himself on the work of others Ether 10:7 Mosiah 11:6
Killed by his own people Ether 10:8 Mosiah 19:20
[Book of Mormon Student Manual, Religion 121 and 122, p. 141]