Elf Dorei to Kizuku Dungeon Harem: Isekai de Netotte Nakama wo Fuyashimasu

Mars, a boy who was reborn into this magical world, is on a quest with his elf slave, Lilia. His goal is to conquer the world's seven greatest dungeons and obtain the forbidden book of magic, which contained extraordinary powers. However, he kept falling behind in his quest progress because he spent too much time making love to Lilia...... every day. One day, in a dungeon, he met Hazuki, a wizard girl from a different party. She seemed cool and mature at first glance, but then she said, "Wow, please make me your slave......!" As she found out about Mars' hidden power, wealth, and male prowess, she became Mars' captive, too! Lilia vs. Hazuki, a heated battle over their master has begun.
(Source: Shueisha, translated)