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He and frontman Abbath comprised the core of Immortal in its early years , with other members fluctuating and little stability until drummer Horgh joined the band in 1997 .
 person: Abbath; organization: Immortal; person: Horgh
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 person: Abbath; organization: Immortal; person: Horgh