Inclusion Criteria:

          -  Have documented initial diagnosis of multiple myeloma according to international
             myeloma working group (IMWG) diagnostic criteria

          -  Meet treatment regimen-specific requirements as follows: Treatment Regimen A
             (teclistamab [tec]-daratumumab [dara]-pomalidomide [pom]) only: Participant has
             relapsed or refractory multiple myeloma and has received 1 to 3 prior lines of
             therapy, including exposure to a proteasome inhibitor (PI) and lenalidomide; Treatment
             Regimen B (tec-dara-lenalidomide [len]-bortezomib [bor]) only: Participant has newly
             diagnosed or relapsed/refractory multiple myeloma and is naive to treatment with
             lenalidomide; Treatment Regimen C (tec-nirogacestat [niro]) only: Participant has
             relapsed or refractory multiple myeloma and has 1) received 3 or more prior lines of
             therapy or 2) is double refractory to a PI and an immunomodulatory drug (IMiD) and
             triple exposed to a PI, an IMiD, and an anti-cluster of differentiation (CD)38
             monoclonal antibody (mAb); Treatment Regimen D (tec-len) only: Participant has
             multiple myeloma and has received greater than or equal to (>=) 2 prior lines of
             therapy, including exposure to a PI, an IMiD, and an anti-CD38 mAb; Treatment Regimen
             E (tec-dara-len) only: Participant has multiple myeloma and has received 1 to 3 prior
             lines of therapy, including exposure to a PI and an IMiD

          -  Have measurable disease at screening as defined by at least one of the following:
             serum M-protein level >= 1.0 gram/deciliter (g/dL); or urine M-protein level >= 200
             milligrams (mg)/24 hours; or light chain multiple myeloma: serum immunoglobulin (Ig)
             free light chain (FLC) >= 10 milligram/deciliter (mg/dL) and abnormal serum Ig kappa
             lambda FLC ratio

          -  A woman of childbearing potential must have a negative serum (beta human chorionic
             gonadotropin [hCG]) pregnancy test at screening and a negative urine or serum
             pregnancy test within 24 hours before the start of study treatment administration and
             must agree to further serum or urine pregnancy tests during the study

          -  A woman must agree not to donate eggs (ova, oocytes) for the purposes of assisted
             reproduction during the study and for at least 100 days after the last dose of study
             treatment

        Exclusion Criteria:

          -  Prior treatment with any therapy that targets B-cell maturation antigen (BCMA): This
             exclusion does not apply to Treatment Regimen C

          -  Live, attenuated vaccine within 30 days before the first dose of study treatment

          -  Received a cumulative dose of corticosteroids equivalent to >= 140 mg of prednisone
             within the 14-day period before the start of study treatment administration

          -  Active central nervous system (CNS) involvement or exhibition of clinical signs of
             meningeal involvement of multiple myeloma. If either is suspected, brain magnetic
             resonance imaging (MRI) and lumbar cytology are required

          -  Known to be seropositive for human immunodeficiency virus