দ্বারা ethics one. This is a partner,companion and lover. Though it is not uncommon for this partnership to break down অথবা death so they will find another but there are some who become a maker of many for several reasons. protection, coven, অথবা just doesn't follow one on one relationships and have many on different levels. This may also include vanity. How many can I bring over.
If we think about the various ভ্যাম্পায়ার in চলচ্চিত্র and literature over the years most have had আরো than one follower. ভ্যাম্পায়ার are supposedly a vain creature... so they'd want আরো than one follower অথবা prodigy to admire them/worship them.
Not everyone can live for আরো than the usual human lifetime. I imagine if its not accidental, the vampire would have to take that into consideration when choosing a companion. A companion would mean something else to a vampire. To live আরো lifetimes আপনি would have to feel young always in your head and probably an a sense of unfinished buisness in your life.